Who on earth would want to advertise on reddit, given the site’s thoroughly unpleasant audience, the notoriety of which has been growing by the month?
Reddit might be able to court the same sponsors (porn sites and such) that sustain the likes of 4chan, as long as said sponsors are willing to associate themselves with a far more misogynist, racist, child porn-defending audience. But this would likely inspire a revolt among redditors, who hold themselves in laughably high self-regard.
I think the contributors to racist, misogynist, and child porn-defending subreddits are only a tiny minority of Reddit's users. Most of the popular subreddits are fairly benign (AskReddit, IAMA, etc.)
Interestingly, all your recent comments seem to be about how you dislike Reddit. Consumption of a chill pill may be in order.
Subreddits like AskReddit do have a lot of racist and misogynist shit posted all the time, esp. those leading questions people post to AskReddit. The Reddit moderating system doesn't make Reddit a safe space for people, so I can see what the OP is getting at in terms of Reddit being an unsafe space.
I find Reddit having a fine audience. Not as good as Hackernews or Stackexchange or so (where good content is a little more valued than on the average forum), but certainly better than the real stinkholes of the internet. Even 9gag has ads.
The reddit audience has changed over the past 5 years due to large growth and the introduction of subreddits. Old users from digg eventually took over reddit. Comments on the sites went from was what intelligent and humorous to stupid and blatant.
Submissions continue to degrade and more cats continue to appear.
As long as you can limit which subreddits your ads are shown on, which I'm 99% sure is already possible, this wouldn't be a real issue for the vast majority of advertisers.
