Please post a comment on which type of video you prefer to watch, and why. For me it goes like this: 1. MP4: Can be played in a normal flv/mp4 player without installing additional software (besides flash), quality is quite good if the video is encoded with the h.264 codec and file sizes are reasonable. However these files usually require a lot of pc horepower, so it's limited to the users with a fast computer. Sites of interest: meevid.com, wuapi.com, vimeo.com 2. Avi: Videos encoded with DivX, Xvid or Lavc. Quality can be quite good, at the cost of bigger file sizes compared to the h.264 codec and can be played on a wide range of computers and other devices (xbox, dvd players etc.). The downside is that you have to install the divx web player to watch these vids online, but that certaintly didn't stop stage6.com from becoming a huge success anyways. Sites of interest: stagevu.com, stagehd.com 3. MKV: The Matroska container provides full support for both ac3 and h.264 while keeping the file sizes down. I don't have any experience with converting videos to this format myself, but it does seem to gain popularity fast. Sites of interest: vuze.com 4. FLV: The most popular and widespread format of them all, but very limited in terms of quality/size. Sites of interest: youtube.com, veoh.com, megavideo.com Sooo.... What do YOU prefer??