As far as we can tell, Kevin Sherman (BubbleGuru on Twitter) must have loved Pop-Up Video back in the 90's, because he has no less than five different video-in-a-bubble services that you can try out. His highest-profile service, Bubble Tweet, starts with a simple redirect URL that takes you to someone's Twitter page. Almost immediately, a small round bubble appears and starts playing a short video starring the profile's owner. Simple, to the point, fun, and free!

To get started with Bubble Tweet, you don't have to register. Just enter a Twitter account name and record or upload a short video. That's it! You will get a custom Bubble Tweet URL that will show you your recording overlaid on the specified Twitter account. A count is kept for how many visits each Bubble Tweet URL gets. Plus, you can create up to three Bubble Tweet videos a day.

Although at first blush this may seem like a cute little toy that you may try once and then forget about (and in fact, it seems most of the folks who have recorded a video have indeed done that), we think that at the very least it adds a face behind the Twitter account. How many times have you visited someone's Twitter and wondered, is that a person or an ad agency or a robot behind that login? Now you have 30 seconds to shine for your viewer. With a bit of creativity, you could use this free service to answer a weekly question, do a quick movie review, spin in place, or even use it to get people to visit your comedy tour like Dane Cook.

Kevin has taken his bubble-video technology and applied it to a number of different online activities, such as electronic greeting cards (Bubble Joy), enhancing any web site (Bubble Comment), and answering questions (Bubble Guru). In real entrepreneurial form, Kevin isn't sitting still with his goal to get the web wired up with short-form videos.

He's even made a StumbleUpon-style random BubbleTweet page where you can just sit back and watch the bubbles one after another. Good stuff.