Flash is the way to go for delivering video on the web. Flash 6 has about 98 percent penetration with the online public and later versions are being adopted even more quickly. Other video players have a far smaller reach, in the neighborhood of 30 to 60 percent, and are extremely limiting in a user’s interaction with the video.

Flash is seamless within the page, thus it doesn't require a user to launch another application. And like other players, the Flash movie can be streamed to get a user quickly engaged with the video.

Another layer of consideration, with respect to accessibility, is the age-old issue of operating systems and browsers. Make sure to test the video, in all browser and OS configurations. True, Flash standards are basically ubiquitous, but little things crop up and react differently in certain configurations. For example, the video can run at a different pace on a Mac versus a PC. Watch out for that as much as you would when developing another web-based application.