I dont understand this, you seem to think that Microsoft has ignored the web when they are in fact one of the largest web companies on the planet. There is almost no company they could buy who would not overlap in concerns. You might argue that some companies are better at certain things or have larger customer bases but this idea that they should buy a web company and quit holding on to the desktop is just goofy.

All that said, one important web asset MSFT doesnt have a strong play in is web analytics.