From their site: Manage your social graph once. Return a list of a services associated with a specific user. Great if you want to learn more about a particular user's other online services (e.g. twitter, digg, del.icio.us, flickr, etc.). Lookup is done via email address, so integration with your existing users is a snap (provided they opt-in to dandyId -- we don't return anything without the user's permission).
The following is a list of how-to and tutorial content that matched your search term. ProgrammableWeb's how-to content comes from two sources; full-blown tutorials that we publish ourselves and other highly relevant tutorials that we find elsewhere on the Web. This list represents on combination of both tutorial types and if you go to ProgrammableWeb's API University, you'll not only be able to find more, they are organized based on your role (API providers or developers who consumes APIs). If you know of a tutorial that would be of interest to the ProgrammableWeb community, we'd like to know about it. Be sure to check our guidelines for making contributions to ProgrammableWeb.