requires an username and password but it has lots of features. They claim to have the biggest database, with over 9 billion searches compiled from 37 sources that include major international, pay per click, meta and regional engines. You can search on spell:keyword, related:keyword, like:keyword and crawl:keyword . The tool will search Overture's data from 16 different countries. There is just too much to list here. Go sign up and get take a peek.