After hearing whispers from a reporter last week that Yahoo was eyeing mobile ad network Quattro, we started hearing similar rumors over the past 24 hours that Apple would be the suitor. Kara Swisher at WSJ then scooped the story and this morning, we’ve heard official confirmation from Quattro.

It’s surprising to some that Apple would do this, but it also makes sense. Growth in iPhone and iTouch usage have put Apple in the position of delivering lots of content (produced by others). A mobile ad network puts a monetization engine behind some of these efforts, in addition to the subscription model it’s built.

As such, it places Apple in the business of mobile advertising for the first time. But it’s not the first we’ve heard of this: The company indicated interest in this direction through the rumored bid for AdMob last quarter. And we all know what ended up happening there.

Speaking of which, we expect more M&A activity in the mobile ad space in the coming months (one of the predictions in our 2010 trend outlook to be released later this week). This could involve the remaining ad networks out there, and others planting various stakes in mobile, such as Yahoo and Microsoft.

These will carry some of the same drivers behind the Google AdMob deal: A need to enhance offerings to advertisers as they themselves increase interest levels in mobile advertising. What this means for the industry: more one-stop-shop ad offerings will make it easier for advertisers.

Combined with an improving economy, this should stimulate mobile ad spending levels.