There are already a few services that make it easy for you to share links to videos on Twitter, including and, but they’re getting a serious new competitor today: ImageShack.

You can either upload videos and tweet them directly from ImageShack’s media hosting service, yfrog, share videos from within another company that uses yfrog. Those include Tweetie, a popular third-party application for the iPhone and Mac computers, and a current yfrog customer.

Importantly, unlike its rivals, ImageShack doesn’t use Flash to play videos. It uses the H.264 codec. The iPhone doesn’t currently play Flash videos but it does play H.264 videos. This means iPhone users can watch videos that their friends share through Tweetie — but not links from TwitVid or

Jack Levin, ImageShack’s founder, showed me a demo on his phone last night, and it was pretty slick. Just tweet out a video, then your friends click on the link and get taken to a full-screen view of the video. ImageShack’s use of this codec also means it can offer higher-quality videos than rivals. Take a look at the screenshots the company made of its service versus, for example — its rival’s screen is clearly more pixelated.

Mobile Twitter videos are likely to get a lot more popular, soon. The iPhone is expected to enable video recording when its software gets a big upgrade this summer. So every twittering iPhone owner — of which there are certainly millions — will be able to film then tweet videos just like they can do now with images. ImageShack is poised to capture that market, building on its already-strong Twitter presence. Levin tells me that yfrog is already being used by 95 percent of mobile Twitter applications.