Well doing research on RSS in depth got me back to microformats it has been something that I was following for some time but lost track in the middle but heard that yahoo tech is using hreview microformat and yahoo is very much influenced by microformats so I searched on google and came across tantek slides of his micorformat presentation on yahoo also came across a very good firefox extension called tails which allows you to find out microformats embedded on the pages that you are currently on.

Looks like rss,microformats,opml are the ingredients along with a killer idea for a successful web2.0 app