Using Social networking data (as well as user preferences, profiles, even browsing history) to give better results looks like the only way (easy way!!), as of now, for any search engine today to improve their results. This is one of the reason why Facebook(750 million active users as of now) is considered a huge threat to google. The notion of Facebook entering the search domain has been around for sometime now (and has been ridiculed by many ). The fact remains that most users would prefer looking at a webpage or buying stuff , if that is already recommended by someone they know (google's +1 or FB's "like","shared" features).
My concern is, this would leave out people who do not use social networking sites a lot. A medical professional might still use google on a regular basis but might not be active in Social network sites , or may not even have a google/gmail id (to get profile preferences).
Another concern is the misuse of these parameters. There are already known ways to boost a website's google rank (some good, some not so good). This was also discussed in class with the example of "miserable failure" keywords pointing to websites of George Bush. There is an interesting term for this concept - "Google Bomb" . There is a good chance that these new social n/w features might also be misused. Here is an article where a user was able to boost his website's ranking only based on "like" clicks, without any backlinks.
This is also mentioned in the previous post's article -
But if Google’s going to start using those +1 votes, the company is virtually inviting the world’s spammers and blackhat SEO magicians to flood its social networking system with fake profiles and fake votes — potentially ruining it and possibly making the problem of search spam even worse.
For these reasons, I think the research on improved IR methods/ranking algorithms should continue with minimal user data.