Recent estimates from Ineum Consulting forecast that mobile advertising revenues will rise by 45% on an annual basis over the next five years to a total of $3.1bn (€2.2bn; £1.9bn) at the end of this timeframe, a 0.6% share of the worldwide market.
  
By contrast, Microsoft's Howe argued that in "five years from now mobile will be 5-10% of media spend," although he added that this development "won't happen all at once; it will happen gradually."

Similarly, he said the medium "is going to be one of the fastest growing segments this year because it is growing out of a small base."

In terms of establishing when the channel will "hit mainstream", Howe predicted this is "probably still a year or more away."

Latin America and Africa, where mobile phone access it likely to outstrip internet penetration, are set to be at the forefront of the medium's growth.

In more advanced markets, niche advertisers, such as "mom and pop" retailers, could also look to employ targeted campaigns on mobile phones rather than using local newspapers.

However, "the biggest bottleneck is going to be having enough case studies where major advertisers have done something really interesting in the mobile space," Howe said.