I happened to be switching between channels the other night and went to enable subtitles for a particular program (a feature of MCE in Windows 7 that I've grown to really appreciate).

I was surprised to see an extra menu appearing - "Interactive TV". Wow, I wonder what it does? Nothing apparently but it is intriguing. I'm not sure if this is something new in MCE, or a new feature for the television transmission in my area.

Photo of Windows Media Center showing 'Interactive TV' menu

A reply to my query on the Australian Media Centre forums suggests this is a new feature that some channels are now transmitting.