Rebirth 10: I'm a Promoter at Tencent

"During matching, the system does not compare coordinates, but only grid numbers." Zhou Qian switched slides, which showed a complex algorithm flowchart. "If two users are in the same grid, they are matched directly; if they are in adjacent grids and meet certain auxiliary conditions, such as both having used the function at night or both having searched for similar keywords, a matching suggestion can also be triggered."

Liu Rui quickly took notes, then looked up and asked, "What's the grid size?"

"Dynamically adjusted." Zhou Qian pushed up her glasses. "The core business district may only be 300 meters square, while the residential area may expand to 800 meters. We will preload a grid map of each city, but the user's device will only store the code, not the map itself. The server will also only record the grid number where the match occurs, without recording any information that could potentially deduce the user's real location."

Lin Shen had been listening quietly until now, then he spoke up: "Has the research institute created an existing codebase for this solution?"

"We have a basic framework, but we need to do a lot of optimization for social scenarios," Zhou Qian said. "Especially the real-time requirements. From the user shaking their phone to grid positioning to matching calculation, the entire process needs to be completed within 500 milliseconds. This requires a high degree of collaboration between the client and the server."

"Resources are not a problem," Lin Shen said to Sun Hui. "Just apply for as many computing nodes as you need."

A soft gasp was heard in the conference room.

The newly joined team members exchanged glances; they had never seen such a bold approach to resource mobilization before.

"The second layer is real-time interaction." Cheng Xiangdong continued to advance the agenda, "The 15-second two-way confirmation requires solving two technical problems: the accuracy of state synchronization and the stability of the system under high concurrency."

He quickly listed the key technical points on the whiteboard:

WebSocket long-lived connection keep-alive and heartbeat mechanism.

Distributed session state management.

Clock synchronization and timeout are unified.

Reconnection and status recovery after disconnection.

"The most difficult part is clock synchronization." Cheng Xiangdong circled the third point heavily with his pen. "User A clicks 'confirm' at 14.9 seconds, and user B clicks at 15.1 seconds. Is this considered a success or a failure? Server time, client local time, network transmission latency... any slight deviation can lead to a terrible user experience."

Wu Feng raised his hand: "Time synchronization can be done using the NTP protocol, but the accuracy of public NTP may not be sufficient."

"Use Tencent's internal network time synchronization server." Lin Shen gave a direct solution. "Set up a dedicated line, do a private deployment, and control the accuracy to the millisecond level. Sun Hui, you coordinate with the infrastructure department to solve this. I need to see the solution this afternoon."

Sun Hui quickly wrote down: "Understood."

"The third layer is user experience and security control." Cheng Xiangdong switched to the final topic, "Liu Rui, are there any special requirements on the product side?"

Liu Rui stood up, walked to the whiteboard, and drew the complete user interaction process next to Cheng Xiangdong's technical framework:

"From the moment the user shakes their phone, we need to build a gradual ladder of trust." His pen moved across the whiteboard, drawing a ladder-like diagram. "The first step, the instant after the shake, is to only show 'Looking for potentially interesting connections,' without giving any location hints or creating anxiety."

"The second step, after a successful match, displays a very brief message: 'A friend who also lives in the tech park is about 500 meters away from you.' The key words here are 'about' and 'friend,' creating a safe, ambiguous, and friendly atmosphere."

"The third step is a 15-second confirmation countdown. During this process, golden quotes can appear, such as 'A good connection is worth waiting for' or 'Two-way confirmation is the beginning of mutual respect.' This is not a feature description, but a transmission of values."

"The fourth step is to set a 15-minute time limit after the conversation begins. The interface design should include a clear time progress bar and quick options for 'Save to Local' and 'One-Click Deletion'. In the last 60 seconds, a gentle prompt should appear: 'The conversation is about to end. Would you like to save these precious moments?'"

He put down his pen and looked at Lin Shen: "The design philosophy of the entire process is: no pressure, only choices; no anxiety, only peace of mind. We want users to feel that this is not a stranger social networking event full of uncertainty, but a safe, controllable, and fun exploration."

Lin Shen listened quietly, then asked, "How can the reporting and risk control systems be integrated?"

"Deep integration." Liu Rui pulled up another design draft. "At any point during the conversation, long-pressing a message bubble will bring up a report option. After reporting, the conversation immediately ends, and both parties automatically block each other. But more importantly," he paused, "we need to build a behavior-based reputation system."

All eyes in the conference room turned to him.

"It's not based on identity-based reputation, but on the anonymous reputation of the device," Liu Rui explained. "Each device has an invisible reputation score. Normal use, completing conversations, and receiving positive reviews will add points; being reported, frequently canceling matches, or sending suspicious content will deduct points. When the reputation score is below the threshold, the matching requests initiated by this device will be downgraded. It's not a complete ban, but rather the matching waiting time will be extended and the matching range will be narrowed."

Zhou Qian's eyes lit up: "This can be achieved at the algorithm level. When performing matching calculations, the device reputation score can be added as a weight parameter."

"But we will reward high-reputation devices," Lin Shen added. "For example, faster matching speeds, larger matching radii, and even, in the future, we could consider some lightweight, exclusive features. We want to create a positive cycle: users who respect the rules will have a better experience, while users who break the rules will naturally be marginalized."

The meeting lasted until 12:30 PM, and the technical solution was basically finalized. Zhou Qian was responsible for the social adaptation of the differential privacy algorithm and delivered the core code in three days; Cheng Xiangdong was responsible for client integration and real-time interaction framework; Sun Hui led the backend architecture and resource scheduling; Liu Rui completed the product interaction design and coordinated user testing.

After the meeting, Lin Shen called Liu Rui and Zhou Qian to a stop, and the three of them went into the small conference room.

The door closed, shutting out the noise from the outside world.

"I'm not too worried about whether the 'shake' feature can be implemented technically," Lin Shen said, looking at the two of them. "What I'm worried about is something else: whether it will be abused, whether it will become... well, I can't find the right word to describe it, but you should understand."

Liu Rui and Zhou Qian exchanged a glance, their expressions turning serious.

"Any social function can be abused," Liu Rui said. "But our design has set up defenses to the maximum extent: location ambiguity makes offline tracking almost impossible; double confirmation filters impulsive users; timed chat reduces the possibility of entanglement; and the reporting and suspension system gives users the final control..."

"Defenses are rigid, but people are flexible," Lin Shen interrupted him. "Have you considered what would happen if someone used ten phones to simultaneously shake their phones in the same location for a mass matching test? What if someone developed a cheat program that automatically clicked 'Start Chat' and then sent spam messages? Or even—what if someone used this function for illegal transactions, such as contraband or fraudulent messages?"

Zhou Qian's face turned pale: "Technically... we can implement frequency limits and device fingerprint recognition. The same device can be limited to a maximum of ten shakes per hour; concurrent requests from the same IP range can be restricted. But this only deters honest users, not malicious users with technical capabilities."

"Therefore, we need to add another line of defense, combining manual inspections with intelligent risk control." Lin Shen wrote a line of large characters on the whiteboard: All data is traceable, all behavior is auditable, but all content is not stored.

"For each match made through the shake feature, the server generates a unique session ID," he explained in detail. "This ID is associated with the region codes of both parties, device fingerprints, shake timestamps, and confirmation timestamps—but never with user identity information. When a user reports a transaction, we can use this ID to quickly locate the session, view fragments of the reported content after the user authorizes it, and permanently ban the device fingerprint if necessary."

Liu Rui quickly took notes, his eyes shining: "This design is great! It protects user anonymity—the server doesn't know who's who—and gives us a management tool—to know which device is causing harm."

"One more thing," Lin Shen continued, "The chat history from the shake feature is automatically cleared after 15 minutes. But before clearing it, the client should pop up a window to remind the user: 'This conversation is about to disappear. Do you want to save it locally?' If the user chooses to save it, the record will remain on the user's phone in a locally encrypted form; if the user does not save it, the record will be completely erased from the world. The server does not keep any copies, so we cannot view it even if we want to."

Zhou Qian was stunned. After a few seconds, she pushed up her glasses, her voice trembling slightly: "President Lin... this is equivalent to completely returning data ownership to the users. The server is just a conduit, just a matching tool, it doesn't store any substantial content. This is more powerful than any privacy statement or legal clause, because it determines at the architectural level that 'we cannot do evil.'"

"Yes," Lin Shen said, his voice exceptionally clear in the quiet conference room. "What WeChat needs to do is not 'we promise not to misuse your data,' but 'we don't have your data at all.' Architecture determines behavior, and the system determines ethics. This is the ultimate form of privacy protection—not through moral self-discipline, but through what is technologically impossible."

Liu Rui took a deep breath. The somewhat messy handwriting on his notebook revealed his inner turmoil: "President Lin, this concept... is too ahead of its time. Internet companies these days, from Baidu to Alibaba to Tencent itself, are all desperately collecting data, building user profiles, and optimizing Google recommendations. We're going against the grain. Won't... won't we be questioned? Won't we be accused of 'not understanding business'?"

"Liu Rui, do you know how QQ got its first batch of users?" Lin Shen suddenly asked a seemingly unrelated question.

Liu Rui was taken aback for a moment: "I've checked the information... It was Mr. Ma who recruited them one by one by sending messages on a forum in Shenzhen in 1999. The first hundred users were all people that Mr. Ma personally talked to."

"Yes." Lin Shen nodded. "Back then, QQ was called OICQ. There were no GG (Girls' Love), no memberships, no games, no QQ Show. It was just a simple, green chat tool. But it captured the most fundamental user need: connection. Now, fifteen years later, QQ has grown into a giant, but it also carries too many burdens: a level system, value-added services, a game platform, the GG system..."

He walked to the window, looking down at the bustling park below: "What WeChat needs to do is go back to basics, grasp the next essential need, and secure connectivity in an era of data overload. Shaking may not bring immediate revenue, nor will it show up as impressive numbers on financial statements, but it will bring trust. And trust is the most valuable asset of a social product, a moat that no amount of Google revenue can replace."

Liu Rui suddenly smiled, a smile of relief, a smile of finding a kindred spirit: "President Lin, now I understand why Zhang Xiaolong dared to hand over WeChat to you, and I also understand why President Ma personally met with you. You're not just making a product; you're defining the rules of social media for the next decade. While everyone else is running east, you insist on going west, believing that's where the future lies."

"Rules need people to follow them, and the future needs products to prove itself." Lin Shen glanced at his watch; it was 10:40. "Go ahead and develop the shake feature. Make it a feature that makes people feel at ease and excited—so at ease that they dare to try it, and so excited that they are willing to share it."

After the two left, Lin Shen stood alone in front of the whiteboard.

The whiteboard was covered with writing: differential privacy, zone coding, double confirmation, canary release, auditable anonymity, data user ownership...

These concepts were too advanced for the internet world in 2010, even somewhat idealistic. But Lin Shen knew that this was not idealism, but inevitability—because he had seen the future.

He witnessed the global panic caused by the Facebook data breach in 2018, the industry-wide upheaval when regulatory crackdowns struck in 2021, and the shift in users from "trading privacy for convenience" to "voting with their feet by choosing safer products." Every act of restraint and self-imposed limitation that WeChat is currently making is preparation for that inevitable future.

Lin Shen rubbed his sore shoulders and neck, preparing to get something to eat before discussing the design of the privacy center with Li Yue and Zhao Yiming.

The phone vibrated at that moment.

It's Zhang Xiaolong.

Lin Shen answered the phone: "Mr. Zhang."

"Lin Shen, Mr. Ma just called me again." Zhang Xiaolong's voice sounded tired, but more so serious. "He asked about the progress of WeChat 1.2. I told him you're proceeding according to plan, but he added, 'Tell Lin Shen not to miss the opportunity because of pursuing perfection.'"

Lin Shen gripped his phone tightly: "Mr. Zhang, we're already pushing things forward at top speed, seven days is truly the limit..."

"I know," Zhang Xiaolong interrupted him, "but Mr. Ma has also received the latest data."

There was a few seconds of silence on the other end of the phone. Zhang Xiaolong lowered his voice even further: "Lin Shen, Mr. Ma didn't say it explicitly, but I could hear his anxiety. Tencent can't afford to lose this battle in mobile IM, especially not to Xiaomi, a company that's been established for less than six months. WeChat currently has the resources of the entire group supporting it, but if it gets overtaken in terms of data, all the pressure will fall on you."

"Mr. Zhang," Lin Shen said, his voice particularly clear in the empty conference room, "please tell Mr. Ma: WeChat will not miss the opportunity. We are simply choosing to win in a smarter way. MiTalk can gain 50,000 users a day, but they cannot solve the fundamental problem: in an era where users are increasingly concerned about privacy, a social product built on data plunder has already reached its ceiling."