EFF staff technologist Seth Schoen writes that Adobe is adding DRM to the latest version of Flash. Why they are doing this is, of course, an interesting question. Schoen suggests that the major motivation seems to be Adobe's business model:
Users may also have to upgrade their Flash Player software (and open source alternatives like Gnash, which has been making rapid progress, may be unable to play the encrypted streams at all). Third-party software that can download Flash Video, like the most recent RealPlayer, will also break. But Adobe now has an incentive to push the use of DRM: it's only available to sites that use Flash Media Server 3 software, which starts at over $4,000 (with extra fees depending on the number of simultaneous streams).