Diigo is similar, but cooler. Below are some cool images that show what your can do with Diigo. Highlight sections of website, take images (even if deleted, you have it), post it notes for questions on websites, not to mention the social part of Diigo. I will keep my delicious account, but new material will be added to Diigo, check out my site: GarthHolman Diigo also lets you join as an educator and get "pro" stuff for free. Not to mention, the educators listserve.
I guess I should mention, I switched browsers to Google Chrome as well. LIKE IT.