Ever get the feeling that there are hundreds of other websites out there you might be interested in, but just don't know where to find them? Try out InSuggest. The site works in three ways: image suggestions, website suggestions and bookmark suggestions. For images, select a few you like and InSuggest will return similar images that you may find interesting.
Enter the URL of a website you like and you will see thumbnails of several, related sites. Drag and drop those you like to the top bar and more recommendations will show up, and so on. Not only a fun tool, but for website owners, it's an excellent way to scope the competition.
Bookmark suggestions work by entering you del.icio.us ID. You will receive listings of other bookmarks across the Web that might interest you. For website owners and marketers, it's also a good reason to get involved with the del.icio.us community - you could find yourself getting residual traffic if this site takes off.
For casual surfers, it's a very nice tool to expand your Web horizons. I've tested the site and it works very well indeed.