Earlier this month JumpTap released a mobile advertiser and publisher survey, which shows both the growth trajectory of mobile advertising and some of the pain points for marketers.
The survey data, collected from 611 agencies, advertisers and publishers, showed that 79% of respondents were doing some form of mobile advertising but most were spending less than 5% of their budgets; the average was 6%. However they expected to increase spending significantly in the coming year.
Targeting capabilities were the number one thing that advertisers were seeking in mobile, with local/geo and contextual the most desired forms. Most advertisers, seeking reach, went first to ad networks and then to publishers.

This week for in New York at Advertising Week Millennial Media is hosting a panel discussion that ask the question: Will mobile eclipse online? Eventually it may. Earlier this month Flurry Analytics showed that available mobile app inventory/impressions would in fact eclipse PC display if those impressions were fully monetized:

This morning eMarketer released new mobile ad projections that estimate US mobile ad revenues to hit $1.2 billion this year.

That's gratifying to me because the mobile ad forecast that Dan Miller and I did in 2009 ago showed North American mobile advertising to reach $1.4 billion in 2011 -- pretty close to the eMarketer forecast.

It's clear that mobile advertising is ramping very quickly, lead by search marketing but mobile diplay is a big driver of revenue and a money maker for many mobile publishers.
BIA/Kelsey has predicted that 70% of mobile advertising will be locally targeted. I have disputed this assumption; although it gets quickly into the question of "what is a local ad?" If it includes location on a landing page or a store finder, yes most ads will offer something like that. Local ad creative is a different matter, however.
At the Borrell Local-Mobile event yesterday publishers spoke about not making much money on mobile but it being a huge growth area and opportunity. The JumpTap survey data illustrates the challenges to publishers -- especially local publishers -- in providing reach and efficiency to advertisers in mobile.