Bing, the Zune of Search engine technology...
Microsoft's stock went up, Yahoo's stock went down. It's obvious to the market, Yahoo loses in this deal. Why? One reason -- Because the obvious role that search engines now play in marketing.
My reason -- Microsoft controls the search engine infrastructure. They own, effectively, Yahoo. They now see all the data first. This will be touted as a partnership, but Yahoo is the lesser partner. The hits can be directed where Microsoft says (With advertising and other search engine tricks).
Sadly, all of this is background noise to what's important -- Google.
Microsoft may have won second place in the light of this new agreement, and Yahoo taken 3rd. Google takes a huge first place -- and that's all that counts in the long run.