Amazon.com is using its A9 search subsidiary to power a new pay-per-click ad network to display targeted text ads on its site.

As anticipated, on Thursday Amazon launched, in beta, Clickriver Ads - its auction-based pay-per-click advertising program, reports ClickZ. Clickriver Ads allows "businesses to place sponsored links on Amazon.com, next to search results and on product detail pages. Clickriver Ads presents a unique opportunity to advertise services and products that complement the selection on Amazon.com," according to the site's About page.

Clickriver ads will run alongside sponsored links from third-party ad networks. It is likely that Clickriver Ads will block competing retailers' advertising on product pages, according to ClickZ.

For now, Amazon has placed limits on advertiser access to the Clickriver Ads beta. "Everyone can apply, although unfortunately we will not be able to accept all the applications," according to the website.

Amazon recently scaled back A9's services, removing both a search-recall feature and a street-level mapping of major U.S. cities. A9's first chief executive, Udi Manber, is now VP of engineering at Google.