The same type of right wing nonsense they are going after now. This type of stuff was all over Reddit/FB/Twitter back then. (Remember all the nutty Obama conspiracy theories?) Surely advertisers back then didn't want to appear next to that content anymore than they want to now.
It's been a while, but I can't say I recall calls to violence, much less ones that were acted on, back then. Of course, I wasn't paying as much attention. Birtherism (which was trump led for a while) was lighter weight than q and the more recent stuff.