StumbleUpon wears a lot of hats: random Web site surfer, social networker, social bookmarker, site reviewer. It's a powerful little add-on for Firefox and Internet Explorer.

One click is all it takes to get going with this toolbar, which encourages random discovery on the Internet based on your interests. The "Stumble!" logo whips you around the Net, but at the your pace, based on categories you choose during installation. Hundreds of topics are available and can be updated at will, with no selection limit. Other StumbleUpon functions are just as user-friendly. A click on the toolbar's "thumbs-up" and "thumbs-down" icons make ratings a cinch, and another click is all it takes to share sites, to update the friends list, to view the rated pages list, to read reviews of the page, to peruse the menu, or to search the StumbleUpon database.

Newer features make it easier to block sites and topics that you never want to stumble across, for the first time or ever again. Occasional use pops up a proprietary nagging page asking to complete your profile if you haven't; StumbleUpon pushes the social aspect pretty hard although it's easy enough to ignore. If Web surfing is the new channel surfing, then StumbleUpon should be your remote.