The Live Search blog announces a partnership between Facebook and Microsoft for search and ads. You can now either "Search Facebook" or "Search the Web" using Live.com. Additionally, adCenter ads will be delivered alongside those search results.
So far, it's good to integrate search on Facebook with search on Live.com to prevent opening a second tab/browser to perform searches. However, as one forum member points out, this looks like an attempt for Microsoft do dominate the search realm.
Other implications of this search partnership will relate to the personal information Facebook has about you and how Microsoft should probably leverage that with this search integration. I'd admit -- if I'm searching on the Web using Facebook, I'd definitely want more personalized results than generic SERPs for any random query.