Facebook said Thursday it would begin allowing users more information about the ads delivered to them, and to block marketing messages they dont want to see. In a blog post, Facebook said its users tell us they want more control over the ads they see and that the huge social network is responding to that. Thats why were introducing ad preferences, a new tool accessible from every ad on Facebook that explains why youre seeing a specific ad and lets you add and remove interests that we use to show you ads, the post said. As an example, Facebook said, if youre not interested in electronics, you can remove electronics from your ad interests.