getting facebook most shared stuff

I was looking at websites like http://开发者_运维知识库itstrending.com/, facediggs.com/ and I'm questioning myself how do they extract the most shared topics from facebook? I would like to build a similar widget for my blog. I searched the API but couldn't find anything.

I have no idea, but here are more sites that might provide additional insight into what you're looking for: http://mashable.com/2010/08/18/facebook-search-services/

I found this page which is worth looking at

http://developers.facebook.com/blog/post/323

Half way down this page is a url you can use to check pages on your site, it returns xml with some good stats. Hope this helps.

Running an FQL (Facebook Query Language) query on the link_stat table.
Below: example url to put in your browser and press enter. It returns xml with true and a count which you can use however you like. This returned 957 last time I tried it. Be carefull using quotes around the url you want to query.

How many facebook shares (total) does stackoverflow have?

Another example with 2 urls