You can create a social network search interface by using Micah Alpern’s ‘Blogs I Read’ Google Hack and/or Feedster. However it appears that Eurekster has taken it one step further:

“Eurekster uses the six-degrees of separation concept to learn from your extended network of contacts and deliver you prioritized results based on the success and proximity of the searches they have done.”

The public beta currently available seems to require a bit more effort than the average consumer “searcher” would be willing to afford. However, I would like to see how well this works within the corporate enterprise — assuming of course you can integrate much of the social network mechanics with existing enterprise directory services such as Active Directory or other LDAP-compliant systems.