Advertisers currently in the beta test should see an alert in their AdWords account informing them that they can create PPA ad campaigns.

Google plans on Thursday to open its pay-per-action (PPA) advertising beta test to a wider set of its AdWords advertisers, including those outside the U.S.

Advertisers currently in the beta test, which began in March, should see an alert in their AdWords account informing them that they can create PPA ad campaigns. And other AdWords users who have enabled AdWords conversion tracking and have received over 500 conversions from cost-per-click or cost-per-impression ad campaigns the past 30 days will automatically be added to the PPA beta test "on a rolling basis."

PPA ads allow advertisers to pay only when a specific action occurs, such as signing up for a newsletter or purchasing a product. While they are often seen as a way to combat click fraud, or invalid clicks in Google parlance, Rob Kniaz, Product Manager for AdWords Pay-Per-Action, insists Google doesn't think of it that way.

Kniaz sees PPA ads complementing Google's other ad programs. "Most advertisers tell us they're insatiable for getting as many conversions as possible," he said. "This really feeds their hunger [for that]."

"If you have some measurable action online," Kniaz added, "this is a good way to monetize it."

Alexandre Douzet, EVP and GM of TheLadders.com, a high-end job search site, said in a statement that PPA advertising helps his company make the most of its marketing budget.

"At TheLadders.com, we are big proponents of marketing efficiency, so the ability to supplement our existing cost-per-click campaigns with a model that rewards qualified leads makes a lot of sense to us," he said.

Google is only showing PPA ads on sites in its AdSense network. AdSense publishers have the option of selecting PPA ads for display individually, by group, or by keywords related to their sites.