Well, from the limited amount of Google ad buying I've done, and some independent stuff that's pretty much it -- of course most advertiser's would be automating the purchase, and I daresay Reddit could even provide a front-end for that. Social media managers (manipulators) are a pretty common position in many companies -- they're already "optimising" story postings, timings, comments, and such. If you're already managing the story submission it's not much extra to manage the advertising.