Last week Zynga CEO Mark Pincus said that they would take steps to remove scammy advertising offers from their social games. There have been a couple of missteps since then, and Facebook responded by taking Zynga’s newest game, FishVille, offline.

Zynga insists they are serious about cleaning up the industry. And today Pincus has announced that the company will remove all offer advertising from their games.

This isn’t a meaningless action. Offers account for 1/3 or so of Zynga’s rumored $250 million in revenue.

All offers will be removed by the end of today, says Pincus, “until we can control their inclusion and presentation ourselves.”

The blog post also discloses that Zynga is an investor in DoubleDing, an offer provider that competes with OfferPal and SuperRewards. DoubleDing was serving the mobile offers that popped back onto Zynga on Friday.

Pincus’ blog post:

Ensuring zynga’s user experience removing all cpa offers:
michael arrington posted yesterday on mobile offerings still being shown in our new game fishville. I want to explain why this occurred and how we are taking more aggressive steps to ensure this never happens again. zynga has not been able to control the ad content as it is managed by the offer companies that we work with. with regards to yesterday’s incident, the offer provider, doubleding, told us this was the result of their failure to remove an optimization queue which was still showing these ads to 10% of pageviews. i want to be clear that zynga had no control over the pages being shown and never filtered them from michael or anyone’s view. we recognize it is our responsibility to ensure that offers which generate a bad user experience are not shown with any of our games.therefore, we are removing all CPA offers across zynga games until we can control their inclusion and presentation ourselves. This will be effective by end of day today. this move is worth it for the long-term user experience and value to our partners like facebook and myspace. yesterday?s mobile offer issue was particularly painful as we had helped fund doubleding earlier this year in the hopes of cleaning up the space and raising the bar on user experience. we intend to influence them and others to improve their ad content and be long-term focused for the success of the social gaming and social networking industries.as I said in my post last monday, my mission is to build zynga into a sustainable consumer service with enduring value to our users. we will continue to do whatever it takes to earn our users trust and respect for the long-term.