Ad technology firm PointRoll sent emails last week to clients warning them that Yahoo! had been disabling some rich media ads on the portal without notice, MediaPost reported, and PointRoll confirmed.

Through PointRoll's "Included" program, web publishers like Yahoo offer PointRoll's rich media ads to marketers at no cost when threshold CPM prices are met.

Yahoo reportedly had informed PointRoll that it planned to leave the company's "Included" program by June, and push its own in-house rich media solution as a free add-on to advertisers instead.

Yahoo bought AdInterax, a provider of rich media advertising solutions to online publishers, last October, for just that reason.

"What's concerning, though, is when I hear about a handful of large advertisers' [rich media] tags getting pulled down and replaced with standard ads," PointRoll Senior Vice President for Sales Andy Ellenthal told MediaPost in an interview yesterday. "That begs the question of 'how many do I not know about?'"

Thus, his email to 5,000 advertisers and agencies on Friday. Ellenthal said Yahoo should honor any agreements with advertisers to pick up the cost for qualifying PointRoll rich media units, at least until June.

Yahoo didn't respond to requests for comment.