However, when I am using a mobile I tend to be doing something with that mobile. Looking at mail, getting map information, watching a video or browsing my cycle of blogs and RSS feeds. While I am doing this I tend to find advertisements rather annoying. They suck down bandwidth I'm sometimes paying for. They get strangled when there's not enough bandwidth to go around. Contrary to print ads, these tend to make me unwilling to deal with the advertiser. Particularly if they're intrusive, animated or noisy.
As many others have said, if you show me pertinent(!) ads when I'm interested in ads I'm happy. If you ram stuff in my face, spend my time and money and keep me from doing what I want to do I'm unhappy. Here's a clue: unhappy people don't make good customers.