The Mention PHP Sample Code by Mention demonstrates API interaction. It presents code to obtain authorization, exchange code with access token, fetch account, and fetch alerts' list. See API documentation at https://dev.mention.com/
There have been a lot of new socially based mashups showing up recently. In fact, we recently topped 700 social mashups. While many of these use the Facebook API or Twitter API, there are many more social APIs. The mashups below run the gamut, though, yes, also include Facebook.