Back in Feb. this year, Google announced changes to the way they integrate social results with normal search results. In the process, they added the ability to publically or privately link your Google profile with accounts on several social networking sites.
Today, if you visit the connected accounts settings for your profile, Google offers a dropdown with six options: Facebook, Flickr, LinkedIn, Quora, Twitter and Yelp.
James Slater pointed out, there're several additional social account options that appear to be hidden in Google's system.
Slater says that each of the existing options is associated with an ID number, but those IDs range from 3 (Twitter) to 18 (Flickr) with several numbers not being used. MySpace is associated with ID=2, for e.g.; Foursquare is ID=10 and Digg is associated with ID=11. Others Slater discovered include Hi5, Microsoft, AOL, Plaxo, Wretch and GitHub.
Now, what self respecting geek would fail to notice that when you select "Flickr" and type in an account name, the page doesn't send "Flickr" back to the server, it sends back a number -- 18. If you choose "Facebook" it sends back 5.
Once installed either, visit https://profiles.google.com/connectedaccounts in your chosen browser. The script will only be active on that exact URL. You should see a number of extra options under "Connect an account" list. Once you've added any of these "new" services, feel free to remove or disable the extension -- it should only be needed to initially show you the other services. Once you've added them to your profile, even if they don't do anything today, perhaps you might get to see them doing something before anyone else.