I believe the Media Access Key is used as you describe. However, the video is not accessible via the web. You need a package called "Tivo Desktop Plus" to be able to download your videos.
http://www.tivo.com/products/tivo-software/index.html
That is, of course, VM either get (or don't need) permission from the TV providers for this, and are willing to offer all the features of Tivo.
I believe they have said they are looking to offer all the features of Tivo, but have not indicated a timescale.