Inevitably, the issue of standards is raising its head again as everyone develops their own XML Schemas and DTDs for TV over the internet applications.
About a decade ago I worked to help establish two standards, SMIL and DAVIC, the former of which is still around, the latter of which sunk without trace.
Now, new proposals are afoot to try and standardise EPG information such as TVG Anytime and XMLTV .
Inevitably, the open source community will advocate one of these standards and Microsoft will go its own way (it's currently using a variety of SMIL2).
If ever there was an application for XML, surely compiling EPG, which are published from hundreds of sources and need to be standardised, is it.