Don’t you just love forecasters? Last November, the Kelsey group reckoned that mobile phone advertising was worth $5bln in 2005 and would ramp up to $15bln in 2010. OK, big numbers. Now along comes Local Mobile Search, a division of Opus Research. Senior Analyst Greg Sterling reckons the US and European mobile phone markets will be counting just $5.08 billion by 2012, up from an estimated $106.8 million at year end 2007. Sterling splits revenues pretty much 50:50 between the US and Europe.

And, no, the drop in forecast isn’t all be down to the ever sinking dollar. The two reports measure different markets and different products. Confusingly, Kelsey’s report is all to do with the local search and classified market whilst Local Mobile Search’s investigations are broader and cover all ad categories.

Someone’s going to have to hire another consultant at great expense to sort out the base lines between these reports. Meantime, all we can say is that the mobile advertising market will be huge. Very huge.