The MEX blog post "Can mobile advertising evolve beyond the mission?" has raised some good points.
I am capturing the key points. ( Read the full article here )
1) Location, time available and mission are three key elements of mobile advertisement.
2) Knowing the context in which user has sent a query, is a must. For this, service providers have to datamine into users history.
3) The advertisement should by itself should be part of the solution user is searching for. Else it would be a distraction,
4) Entertainment service could be one such form of advertisement.
I do not agree much with the point that datamining into users history, is the only way. It seems too costly and un-optimised approach. But, there is little to suggest, how else this could be then done ;(