In Suggest lets you provide a website you like, and then shows you a bunch more it thinks you’ll like. More interestingly, you can do the same with your del.iciou.us bookmarks (you can also use images).
I used it to find some good sites helpful to English Language Learners that I didn’t know existed. Others might find it helpful, too.
I really like the visual aspect of it! The del.icio.us related search worked best for me – the website results were only loosely related. Nice one though.
The site I suggest is Pitch Buzz. It’s one of the most epic social networks on the internet. Pitch Buzz is a social developmental community for developers, musicians, and graphic designers that allow members to meet new friends and a place to showcase their projects.