Everyone's piling on Jerry Yang, saying Yahoo's founder-CEO needs to go. Why? The weak stock that provoked Microsoft's unsolicited bid may have been the result of his absentee ownership over the years. But Yahoo's deeper problem is the rot in its technical prowess. And that has everything to do with the quieter cofounder, David Filo. Filo has stayed behind the scenes, but wields considerable power over Yahoo's infrastructure. Requests for more hardware go through him, for example. When Yahoo executive Jeff Weiner joked in an internal all-hands movie about not going through IT because it was "too much paperwork," the audience surely laughed because they knew exactly what he meant.

In every jest, there's a grain of truth. Later in the movie, Filo appears in a disorganized office, while Ash Patel, the executive ostensibly in charge of Yahoo's platforms and infrastructure, cleans up around him. Not a bad metaphor, except that insiders say they're surprised if Patel even does the clean-up work.

While Google's engineers are awash in a sea of computing power, and are challenged to come up with ideas to use it all, Yahoo's developers cope with an IT infrastructure that is at once too centralized and too disorganized. New CTO Ari Balogh has talked about fixing Yahoo's spaghetti code with new layers of APIs, or ways for independent developers to access Yahoo's websites and data. But making Yahoo more open to outside programmers won't fix the underlying problems with the company's code and infrastructure. Former Yahoo engineers talk about servers that its datacenter operators are afraid to unplug, because no one knows what they do.

It's no wonder, really, that Microsoft executives had talked about discarding Yahoo's technology and introducing their own if they bought the company. Microsoft may be no great shakes when it comes to Web technology, but having started later, there's less accumulated cruft to scrape off. Until Filo is pried away from his iron grip on Yahoo's servers, and do-nothing layabouts like Patel are fired, it's hard to imagine things improving at Yahoo.