Y! search marketshare is falling. I don't have the numbers in front of me, but I seem to remember their search revenue falling faster than marketshare, ie even their revenue per search is declining. Lots of Y!'s money from display/brand advertising on their site families, which is why Y! mail is so crucial. Unlike google where display ad revenue is on other sites, Y display ad revenue is on their sites: mail, dating, news, finance, sports, etc. Y! mail in particular was a key leg of this monetization strategy which is why its neglect is so appalling from a financial perspective. See also the giant RMX fuckup -- Y! should have been ADX/appnexus but yahoo did what yahoo does.