Why not have advertisers partner directly with mods and allow some sort of revenue sharing?

The concern seems to be offensive/weird user created content might be displayed near an advertisement. Well, the mods have control over the content.

Mods could chose whether or not to enable advertising and could chose whether to curate content to maximize click-throughs or not.

Ads could be programmatically targeted towards subreddits and individual comment threads rather than users.