Apple’s iAds are hitting a rough spot, Erik Schonfeld writes for “TechCrunch” (http://macte.ch/RRGTB). He says that, across the board, several developers he’s spoken to confirm that “fill rates” for iAds dropped drastically after the New Year and have yet to recover.

The fill rate — what percentage of the ad inventory is actually filled with an ad — for two separate developers plummeted from 18% to 6%, Schonfeld writes. And in a few instances for some newer apps, none of the ad slots were getting filled, compared to nearly complete fill rates from other mobile ad networks, he adds. Others report better fill rates but as one developer says, “They have definitely come down.”

One reason for the dip could be just seasonal. The fill rates and advertising budgets across all ad networks in general take a hit after the holiday, Schonfeld notes. But there seems to be something else going on here as well, he thinks.

“The general consensus among the advertising community is that it is a product they don’t want,” one mobile ad tech CEO told “TechCrunch.” The iAds business “is hurting,” he says.

iAds combine the emotion of TV advertising with the interactivity of Internet advertising, according to Apple CEO Steve Jobs. He adds that iAd, which is built into iOS 4.x, allows users to stay within their app while engaging with the ad, even while watching a video, playing a game or using in-ad purchase to download an app or buy iTunes content.

Developers who join the iAd Network can incorporate a variety of advertising formats into their apps. Apple will sell and serve the ads, and developers will receive 60% of the iAd Network revenue, which is paid via iTunes Connect.