Google Social Graph API shows the power of microformats
XFN (XHTML Friends Network) is one of the microformats, I have been using for sometime. I have used (where)whenever I can.
XFN goes more interesting and would become more popular with Google’s Social Graph API .
Google Social Graph API allows you to find all such social connections using XFN and FOAF. Thousands of pages/feeds already have XFN and FOAF data.
There are XFN Graphing tools/libraries but Google provides the similar thing in the form of webservice (API), which takes different parameters and returns JSON as output.
This is going to push XFN microformat usage and I am already seeing the effect, some of my friends/acquaintances have edited links on their blogs/pages to add XFN data, so am I doing now 
Technorati tags: xfn, google, social, graph, api
microformat
