Our mashup Social links has been updated.
Lets you search for sites associated with the given URL (e.g. other sites from the same author) as well as for the links (recommendations) in the social networks.
You can directly set your URL and search type in the request too. For example:
http://news.ycombinator.com - more ycombinator
dzone.com - links to dzone
P.S. check out also Whois for Twitter