Where it went wrong for Jerry Yang
economist.com
economist.com
Inevitably, this process destroys the soul of the company. The people who sold them companies mostly didn't stick around (pg!) because they realized there was no soul.
It is very hard to repair such companies (I never say impossible, but very hard!). The comparison is not Apple, because Apple was never built that way. Even in its darkest hour, it had a soul. To give a more relevant contrast, I believe Sun can be repaired, but alas, the longer management fiddles, the more difficult the task becomes.
Find something you're good at, do it better than anyone else, and keep doing it until it doesn't work anymore. Yahoo failed to do any of these things -- they've thrashed around for years, and don't bother to hire competent people to do the few things they were once pioneers at. Very sad.