I covered at the Search Engine Roundtable this morning that some AdSense publishers are automatically being forced into trying out Google's Pay Per Action ads.

Google sent out emails to select publishers, notifying them that a portion of their ads will be serving Google's pay per action ads. That means instead of these publishers earning money on a per impression or per click basis, they can only earn money when an action is completed by the user.

This will only impact about 5% of a publisher's ads, plus publishers can opt out by emailing Google. But if no action is taken on part of the publisher, that percentage of ads will not be the usual pay-per-click type.