For Web inSuggest, just put in the address of a site to get recommendations for similar sites.
I used Wetpaint‘s home page and got the following top eight results:
Since the first two sites in the lefthand columns (Wikispaces and PBwiki) are the most closely related, I’m guessing that you should read down the first column and then down the second one to see now the results are ranked.
Given how little similarity (other than being web 2.0 applications) there is between Wetpaint and the other six hits, I’m not very impressed with the results I got. Apparently someone has tagged the sites that come up, but I’m not sure who does that. I couldn’t find a lot of information about inSuggest on the main page.
At some future time, I’ll look at Bookmark inSuggest.