Not long ago, Stack Overflow was where the world's programmers went whenever they got stuck. Today it is one of the clearest casualties of the AI boom. Prosus, the international arm of Naspers, has cut the value of the site by nearly 60% in its latest results, and has now written off 87% of what it originally paid, about $1.5 billion.
A R24 billion bet gone wrong
Prosus bought Stack Overflow for $1.742 billion in June 2021, roughly R24.2 billion at the time. The bet was that the go-to question-and-answer community for developers would keep growing. Instead, the site has been overtaken by the very kind of technology it helped train. Coding assistants like Anthropic's Claude Code, Cursor and Windsurf, along with chatbots such as Claude, Google's Gemini and ChatGPT, now answer the questions developers used to post to their peers.
The drop in usage is stark. At its pandemic peak, Stack Overflow fielded around 300,000 questions a month. Today it gets about 6,000, sending activity all the way back to where it started.
Still profitable, but worth a fraction
The write-downs have piled up. This year Prosus knocked a further $280 million (R5 billion) off the site's value, plus $54 million (R960 million) against its brand and customer relationships. Having entered the 2026 financial year valued at just $564 million, Stack Overflow is now carried at only $230 million.
Oddly, the business itself is not dying. Revenue actually rose 12% to $129 million in the year to March, and it swung to a small profit of $12 million from a $9 million loss the year before. The problem is not that Stack Overflow makes no money; it is that the market no longer believes it is worth what Prosus paid.
The wider picture for the parent is far healthier, with Naspers reporting record results, revenue of $10.8 billion and core headline earnings up 14% to $3.6 billion. But Stack Overflow stands as a cautionary tale of how quickly AI can hollow out a once-dominant platform, and a reminder that even the smartest buyers can misjudge how fast the ground moves beneath them.
