Ravelry.com

I recently discovered Ravelry, and its sleek layout and fantastic aggregation makes me wish I'd thought of it first. I highly recommend it to any knitter using the internet. It offers individual project pages, space to document your yarn stash, and a great community interface including forums, groups, and friend networks. My favorite part is the pattern search. Patterns are indexed from both books, blogs, internet resources, and personal uploads from members and can be easily searched by keyword, yarn, needle size, or gauge, and more! The only downside is that you must wait around four days for a membership. I still highly recommend it. It even has blog integration. Find me on Ravelry as Mystitat, and check out my projects!