ORIGINAL ARTICLE: http://www.readwriteweb.com/archives/future_of_search_social_relevancy_rank.php
The article talks about the importance of prioritizing search result, or stream of posts, not based on chronological order, but based on social relevancy, or social network of followers of oneself and people he or she is following.
What we are about to get is a Social Relevancy Rank. Whenever you search streams of activity, the results will be ordered not chronologically but by how relevant each is to you based on your social graph. That is, people who matter more to you will bubble up.
The author brought up improvement ideas for mainly Twitter, or also for any SNS. Main points are:
1. The result of search query, or the front loaded posts should come initially from the relations to myself. But it limits the result, because not everyone has opinion or information about the search query.
This sounds awesome, but there is a problem. “Wilco” works well as a query because the band has just released a new album, but many other queries would return no results. Simply put, your friends on Facebook and people you follow on Twitter can’t possibly have an opinion on every topic you may be interested in. This is a problem of sparse data: trusted opinions are scarce.
2. Since the trusted result from the level-one relations is limited, expanding the network to include the relations of the relations is necessary. This expansion can also be based on likeness of people even outside of the relations.
Another step could be to include people with similar tastes, so-called taste neighbors. This approach is common among vertical social networks such as Last.fm, Flixster, and Goodreads. These networks have ideas about which people, other than your friends, are like you. However, this is a costly calculation and takes time.
3. Using the number of followers as a measure, a few of the relations can be titled as opinion leaders or the influencers among the crowd. Give higher order to their opinions in the search results or the stream of posts.
In the absence of any other metric, someone who is followed by hundreds of thousands of users is likely more relevant to you than someone you don’t know at all. Using number of followers as a weight might be a good way to order the rest of the activity stream.
I think this relevancy rank can improve what Twitter, or stream based publishing systems have been good at. For their currently chronologically ordered search results of stream of posts to be more useful or more easily to be found and processed, the additional sorting mechanism based on this relevancy ranking is crucial. Depends on the level of openness of the service enabled by APIs, the application of this system may come much quicker and may be developed to become superior service than the original.