This has been happening for awhile for instance in the UK, Channel 4 used Myspace and Bebo to market and launch this youth programme "SKINS",, plus has online exclusive previews or web only programme episodes. Plus with http;//www.channel4.com/4od 4on demand allows to access to 1000's of programmes and the ability to download and view at a later date.
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http://www.e4.com/skins/
http://www.channel4.com/video/skins/index.html
Also BBC I-player also allows a similar offering as well as ITV later.
http://www.hd-productions.biz