Microsoft is conducting a closed beta test for an advertising program for placing text ads on publishers' sites.

Microsoft's adCenter has sent out a limited number of invitations to advertisers for the pilot test of the program - ContentAds - which will initiallyplace contextual ads on Microsoft properties such as MSN Money, MSN Real Estate and Windows Live sites, among others, reports MediaPost, citing a post on the JenSense blog. The pilot is expected to launch in the fall and will likely be extended to other publishers' sites.

ContentAds will be capable of using demographic targeting, geo-targeting and incremental bidding tools, according to JenSense. The new offering would bring Microsoft's adCenter platform in line with Google AdSense and Yahoo Publisher Network.

"From an advertiser perspective, we know that we'll buy MSN contextual. The harder challenge will be for them (Microsoft) to get that inventory, particularly with Google locking up all the key partnerships," Josh Stylman of Reprise Media is quoted as saying.