Google and eMail AdWords
Based on a reuters story (via Forbes), it seems that Google is trying out linking their AdWords to eMail. This might be at least very viable for newsletters, which come in full html form most of the time anyway, but they can already be found in some of these newsletters. That means it must go broader than that.
_The Mountain View, California, company, which has recently made several e-mail related acquisitions, is working on a way to serve advertising to an e-mail at the moment it is opened, people close to the company said._
They might even go as far as providing their own eMail services, at least based on rumors, but I somehow doubt that. We’ll see how it goes though.

