Social search had been on my mind for two and a half years now. Back then, I expected Google (Nasdaq: GOOG) to buy Twitter and use the microblogger's conversational technology to transform search. Microsoft (Nasdaq: MSFT) couldn't remain idle, I argued, calling on CEO Steve Ballmer to make a bid for Twitter before it was too late.

"When it comes to search, it's important to understand the sources to which we ascribe value. Friends are more valuable to us than strangers, but strangers also have value. Social networks have seen to that by providing a mechanism for indexing groupthink [and] Twitter aggregates these digital conversations better than any other platform on the Web," I wrote at the time.

Microsoft is finally listening. Last week, Mr. Softy expanded its partnership with Facebook to include deeper integration with the Bing search engine. The idea: Let your friends help you make better decisions about what to read, where to travel, what to buy, and so on. Here's a closer look at how the two are cooperating:

Your thank-you card is in the mail, Mr. Zuckerberg
Clearly, Microsoft wants Bing to become a legitimate alternative to Google. Success has come slowly but it is coming. The most recent data from comScore shows Mr. Softy's search engine joining Yahoo! (Nasdaq: YHOO) as the only two to gain share again in April. Adding social features should continue to aid the cause.

Even so, Microsoft shouldn't get all the credit for Bing's success. Facebook's hatred of Google probably also has something to do with Mr. Softy getting more social. The Big G aggregates all sorts of social data from its own sites and Twitter, and its "+1" feature acts as a kind of social signaling. Only deep Facebook integration is lacking. The Social Network's response? Why to bear-hug Bing, of course.

Whether these feature additions will mean more market share for the junior search engine remains to be seen, but friend-enabled filtering may be exactly what overstimulated searchers need right now. Do you agree? Disagree? Let us know what you think about Google, Bing, and the future of search by using the comments box below.

The Motley Fool recently introduced a free My Watchlist feature that allows users to stay ahead of the curve and keep up to date on how Microsoft and its competitors are faring in the fight for search market share. Add these companies to your watchlist today: