Google has made a couple of pretty major announcements regarding its online advertising options today:

1. Pay-per-action beta test  [Inside AdWords]
2. Now accepting applications for new referrals beta  [Inside AdSense]

These announcements are big news because they both make significant changes to the advertising system that has helped Google's revenue soar to its now-lofty heights. Advertisers have been asking for more options.  Publishers have been asking for more options.  These announcements, respectively, address both.

The pay-per-action beta test allows advertisers to use a specific action on their website - such as a sign-up or purchase - as the basis for their AdWords ads.  Under this system, advertisers bid on a price they're willing to pay for each action.  Maybe it's $1 for a sign-up.  Or $3 for a purchase.  Using the AdWords ranking system, Google will collect fees if, and only if, the specified action is taken.

Some advertisers constantly battle with click-fraud and other CPC-based issues.  This new model would allow them to restrict the money they're paying to valid customers who actually do something on their website.

On the publisher's side, Google is making it easier for AdSense users to pick and choose which referral ads are displayed on their sites.  Using keywords, publishers can search for referral units that would be of interest to their readers.  The pay-per-action ads are directly linked to this new feature because it is these ads that publishers will be able to scour through.

As of right now, the referrals beta is open to a limited number of publishers who sign up here.  The pay-per-action ads are on a continually rolling basis.  You can request inclusion in that program here.