Monday, March 5, 2012 at 4:39 pm.

Henry Blodget: Advertising already a $1 billion business for Amazon

Amazon, for its part, is now hiring aggressively to build up its advertising business, which, according to one industry source, already does more than $1 billion of ad revenue a year.

One such hire is Jamie Wells, an ex-agency guy who just did a couple of years at Microsoft’s mobile advertising division. (His Twitter handle recently changed to @JamieWellsAMZN.)

As Henry notes, advertising on Amazon’s site is already a big business.

But don’t overlook its opportunity in mobile advertising. Amazon sells ad-supported Kindles (hiring!), the Kindle Fire, and runs an app store for Android apps. Lots of inventory there, and it’s only going to grow.

And thanks to its e-commerce business, it can charge many advertisers on the way in and on the way out.