While Google is extremely public with their best practices for search engine optimization, they intentionally keep the Google algorithm semi-private, in order to prevent spammers from manipulating the system.
So, when Facebook came out and said –  “Here’s EdgeRank, the Facebook Algorithm. And here’s how it works.” – the Web world took notice. Now, this is a very different kind of algorithm of course. It’s in regards to what shows up at the top of your Facebook news feed if you have “top news” selected.
This EdgeRank algorithm consists of three components. Your “top news” is based on your Affinity with the source (the number of times you have interacted with the source in the past), the Weight of the news (the numbers of times users have interacted with the piece of content) and the Recency of the news (time since the social content was posted).
Now, this is helpful. But there’s no big surprise as to why the algorithm is public…it’s hard to manipulate. Besides creating content that a lot of your fans will want to interact with…oh, maybe that’s the point.