Months ago an SMS provider advertised on reddit. Rather than downvote or ignore the link, there was a veritable flame war of people signing up for the beta just to waste the advertiser's time and quite a bit of animosity going back and forth. Even though most of the people in that conversation wouldn't have utilized the service, they attacked the advertiser because anything involving SMS must be spam.

Having witnessed many cases where redditors attacked, I would never consider advertising there. I can only imagine most of their advertisers advertise once and never again.