Why no Kindle ad platform?

I've been thinking a little bit lately about the NYT and the Kindle, and wondering why you can't just get the newspaper on this increasingly popular device.  Nicholas Carson wrote yesterday about how just giving everyone Kindles would be cheaper than printing and delivering the paper.  Then he wrote:

"Are we trying to say the the New York Times should force all its print subscribers onto the Kindle or else? No. That would kill ad revenues..."

That's when it hit me.  Why on earth doesn't the Kindle have an ad platform?

It's funny because an auther recently asked me about how she could make a little money from distribution of her e-book about careers online, and she said that she had seen some professional development books for students that had been sponsored by companies looking to recruit.   I told her about all the problems with print advertising--the fact that it wasn't measureable at all.

So, if print is going to die because you can't measure the ads and they're not compelling, then why is aren't electronic readers like the Kindle opening up ad platforms?

Imagine that every other NYT article on the Kindle comes with a targeted ad that you have to skip past to read.  That's not so bad... and if you really don't want to see the ads, you can become a subscriber.  The ads would be pretty targeted, because Kindle knows you who are, and knows what else you're reading.  In fact, Amazon knows quite a lot about you and an Amazon ad platform should have a lot of data about you to work with.  They could add the data from their payments system as well. 

This could make Amazon a serious player in the advertising market--a viable threat to Google's market share of ad spend.   Am I missing something here?