iPad Only: The newest version of the StumbleUpon app for iPad includes a "social bar" at the top of each stumbled page that will highlight a friend or another user who also liked the page so you can connect.

iOS/Android: Previously mentioned time-passing, sometimes productivity-killing StumbleUpon has just released an iPhone and Android app, tailored specifically to a mobile browsing experience.

Yahoo Pipes mashup SnackUpon takes the ideas behind two popular web applications—Delicious and StumbleUpon—and creates a customised RSS feed that delivers content you might like based on your Delicious bookmarks. The idea is brilliant: You already subscribe to sites with your newsreader because they deliver content that you like, but you don't have much control over what content the publisher of that site covers. With SnackUpon, it's like you've created a blog that publishes content based solely on your likes. Granted, that assumes the SnackUpon works as advertised, but after testing it out on my Delicious account, this is one feed I'm planning to keep in my newsreader. If you plug in your Delicious ID, let's hear how well SnackUpon matches your taste in the comments.

SnackUpon

Windows/Mac/Linux (Firefox): Site-finding service StumbleUpon has taken full advantage of Firefox 3's "Awesome Bar" by integrating its browser toolbar/extension with Firefox favourites. A new option in the latest version of the previously highlighted StumbleUpon add-on lets you download all the sites you've rated with a thumbs up/"I like it!" into your bookmarks, giving you as-you-type access to that last cool link you saw but can't quite remember. Your recent favourites and their tags are also stored in the browser's "Recent Bookmarks" and "Recent Tags" Smart Folders, helping your organize your idle-time browsing. StumbleUpon 3.23 is a free download, works wherever Firefox 3 does. StumbleUpon 3.23