I'm not sure what you mean by "adaption" - sounds like a blend between "adoption" and "adaptation" - but really the fact that a language like SMIL uses XML syntax is neither here nor there. There are good engineering reasons for building on XML, but the important thing is what facilities it offers to its users, not what syntax it uses underneath the covers.
There are thousands of vocabularies built on top of XML, and SMIL is just one of them. Generally speaking, if you ask a question about a specific XML vocabulary on a general-purpose XML forum, then only 1% of the people on the forum are likely to know anything about it. You'll have to look elsewhere for the experts.
Most of what I have read about SMIL describes it as a format for multimedia presentations. I haven't often seen it described as a vehicle for integrating TV and the internet. But who knows...
Michael Kay
http://www.saxonica.com/
Author, XSLT Programmer's Reference and XPath 2.0 Programmer's Reference