Mobile advertising will continue to play a major role in Google’s revenue going forward. While the jury is still out, so to speak, on the proposed acquisition of AdMob, Google has been placing a great deal of emphasis here at Google I/O on the fact that it already knows a thing or two about advertising.

In fact, AdMob really hasn’t come up a whole lot in the discussions that I’ve been witness to. But that hasn’t stopped Google from talking about various mobile ad formats its offers. A portion of a lengthy keynote delivered Thursday morning was devoted to this.

Google VP, Engineering, Vic Gundotra had the following to say (paraphrased):

It turns out we know a little bit about advertising. This year is Google’s tenth anniversary of providing ad solutions. We’ve learned a few things. if you want a healthy ecoystem, you need advertisers and we have hundreds of thousands of them. we’re not new at this game…

He reminded everybody that Google has Doubleclick, AdWords, AdSense, and Analytics. He then revealed some new expandable ad formats for mobile. More info about Google’s mobile ad formats can be found here. Google is expanding its click-to-call ads to mobile content and apps as well. More on this here.

Gundotra said in a Q&A that the company is being careful about ads so they span both apps and mobile sites.

When it comes down to it, mobile ads mean money for developers. More importantly, they mean motivation to innovate with mobile apps, which of course is critical to Android’s success.

Apart from monetizing the apps themselves, mobile ads can greatly contribute to the discoverability of mobile apps themselves.