If you have used DomainTools (formerly whois.sc), you may have appreciated its Reverse IP tool, which shows all the websites hosted at a given IP address. For a shared webhost machine, this can be several thousand sites but you need a paid account to see more than a sample.
Live Search IP: Operator
I could not find any discussion about the IP: search operator at Live Search, so it might be new. Live Search has rolled out quite a few enhancements and this could be one of them. Give it a try, e.g.
I have a few sites hosted there (asmallorange.com) under one account. I am not sure if there are really 161,000 sites hosted there, but it is not out of the question, particularly when the server is displaying pages very slowly.
Such information is useful for SEOs who need to check if a competitor using similar keyphrases is also hosted. I have not had the chance to test that theory, but it would be impossible to go through 161,000 sites manually to find out. Fortunately, you can add a search term to the IP: operator, e.g.
This shows if any sites are featuring Amazon content. This returns a much more manageable number that can be checked manually.
You could also use it to see if any other sites hosted there have adult or gambling content, using appropriate search terms.
For such a purpose, Live Search is better than DomainTools.com’s Reverse IP tool.