Dave Zatz runs a very popular gadget blog on Zatznotfunny.com. First off this does not look like its going to be an Adsense competitor, the ads are going to be CPM  impression based and not pay per click, so I don’t see this being a parking alternative. Of course Amazon could change their mind down the road. The program is invite only currently to a select group of Associates.

Tech Crunch wrote:

According to Amazon’s description of the new CPM ads, the ads are tailored to the user using Amazon’s personalization technology. You’ll be paid for each impression you serve, and you can specify a target CPM minimum. If Amazon can’t meet the CPM target, your ad request will then be “passed back” to your specified ad network.

Dave Zatz blogged:

Well, beyond Amazon sales, select Associates have been granted early access to a whole new program of banner advertising – beyond Amazon inventory and paid per impression, versus a sales commission.

Amazon CPM Ads feature display ads from Amazon and other high-quality advertisers. Ads are tailored to the user using Amazon’s personalization technology. You will be paid for each ad impression you serve, and you can specify a target CPM minimum. If we can’t meet your CPM target, your ad request will be “passed back” to your specified ad network. 

If we can’t meet your CPM target, your ad request will be “passed back” to your specified ad network. You get:

• A guaranteed amount for every ad impression
• Attractive ads from Amazon and other brand-name advertisers
• Easy set-up and management
• Ads matched to your users based on Amazon’s personalization technology
• A program designed to work with your existing ad network or ad server

Read the full article here