Teletext services could be transmitted with digital television signals, both satellite and terrestrial, and are a standard MPEG feature. A set top box will automatically decode the data and send them over the analogue outputs, or superimposes the decoded page on the video output.
Satellite broadcasting for Italy, Germany and France are still sending Teletext pages.
I've experience with the MHP services on terrestrial television in Italy. Simply put MHP services are totally and utterly slow, even if MHP decoders are more costrly due the bigger CPU they have to run Java ME, instead of use only the computer power equivalent to a Z80.
Worst of all the user interface between various broadcaster is different, even if they're sending teletext-like news and it's too easy to put animated adverts everywhere.