Delicious is a free social bookmarking service that allows you to tag, save, manage and share Web pages all in one place. With emphasis on the power of the community, Delicious greatly improves how people discover, remember and share on the Internet. Can use with Firefox and IE. Bookmarks stored on Delicious servers. Easy to backup locally.
Zotero is a free citation management software for Firefox. Use it to save, organize, and present online citations. 2.0.3 is the latest version, and it allows for backup on Zotero servers.
If you want to make your online life to run smoother and more efficiently, consider using an assortment of free Google Apps. I daily us Google apps such as Calendar, Alerts, Docs, iGoogle, Books, Checkout, Picassa, Chrome, Earth and more!