The Microsoft Bing search engine will soon integrate Facebook Likes more prominently into its search results. Bing added Facebook Instant Personalization and began showing Liked results at the bottom of result pages in October. Now a Facepile of friends who Liked a result appears directly below the result.

Users will be able to factor social recommendations into their normal search behavior of choosing between results. The integration doesn’t appear to be live quite yet, though.

Microsoft has been rapidly expanding its Facebook integrations this last week, launching a new version of the Bing Bar browser toolbar that shows Facebook notifications, messages, and photos, and adding Facebook Chat to Hotmail.

Google’s ongoing tension with Facebook has led it to cease displaying Facebook Page updates after starting to in February 2010, and integrate social data from Twitter into search results rather than Likes. However, users must be logged into their Google account and have explicitly connected their Twitter account, while Facebook users don’t have to explicitly connect to Bing to get social results. Combined with Twitter’s smaller total user base, this means many more people will see social search results on Bing than Google.

While Google still dominates search, and probably will despite Bing’s new integrations, its lack of Facebook content is becoming increasingly apparent. If Google doesn’t come to an agreement with Facebook, it may lose users who want to navigate search results with the help of the Likes of their friends, not their tweets. After all, a friend could have posted a link to Twitter for any number of reasons.