It's sad to see Yahoo flounder like it has. Yahoo has made a number of very smart acquisitions (
del.icio.us,
Flickr,
Upcoming, and many others), but they haven't been able to match Google's ability to monetize search.
Of course, Yahoo has it's own ad network that competes with Google AdWords, but Google dominates that space (and therefore, gets most of the business -- and money). And in search, now people don't even talk about
searching for information; they
google it!
The Microsoft offer undervalues Yahoo, in my opinion.