MediaMall, the folks behind the popular PlayOn media software, just announced the closed beta of PlayLater, a so-called DVR for online video. The service, which is available in a closed beta starting today, allows users to "record" online programming from over a dozen service for viewing later either on the computer it was recorded on or a device loaded with the retail version of PlayOn. Believe it or not, the term DVR is actually appropriate here. I've used the service and it actually records the programming and wraps the video file in a DRM-laced .plv container that's only playable on approved programs. How does it work? I have no idea, but it does and MediaMall's breakaway success with PlayOn says this company knows media streaming.