If you’re using Firefox, Internet Explorer, or Flock, the Diigo toolbar has all the features you could want - bookmark, search, highlight, and organize all your Web pages right from the toolbar. If you’re not into those browsers, though there’s a great bookmarklet that lets you do most of that with any browser.
I use Chrome, and all the functionality I need is built right into the bookmarklet. Delicious becomes more difficult to use outside of Firefox (there are bookmarklets, but they pale in comparison), and Diigo keeps on working fine.