I hope Web 2.0 isn’t going to be about these types of giant mergers. Yahoo has bought two of the major 2.0 players in the last year: del.icio.us just recently and Flickr in March of 2005. For those of us who like to see the smaller players around, this was sad in itself. But so far, at least with the Flickr purchase, Yahoo is not getting in the way or changing the rules (at least in any significant way). And Yahoo is a Microsoft competitor, as is Google.
So if Yahoo bands with Microsoft that leaves Microsoft and Google. Neither is known for transparency and both seem to strive for world domination (at least some of the time).