Yet another study has been released claiming that mobile is the next up-and-coming form of media - and advertising will play a crucial role, according to eMarketer.

The total number of mobile TV and video subscribers globally will rise from 40 million in 2006 to over 750 million in 2011, and paying subscribers are forecast to reach nearly 200 million, with resulting revenue of nearly $13 billion, according to the study.

But while advertising is bound to be important in the mobile video value chain, nobody is quite sure exactly what that means, says eMarketer senior analyst John du Pre Gauntt, author of "Mobile TV and Video: Big Dreams for the Smallest Screen."

"It's a mistake for marketers to assume there is some universal attraction or repulsion among users to the idea of watching video or television on a mobile phone," Gauntt is quoted as saying.