People won’t mind. If a given post isn’t awesome, it’ll just quickly move down the feed because it won’t get votes, out of sight.

Obviously, don’t spam a post every hour, but posting regularly means that there’s often that one new post people might find in all, helping them find their way around.

Basically, to maximize discovery while being as non-spammy as possible, you’d make one post whenever the previous one is too far down the feed to get scrolled down to. Any more, and you risk annoying uninterested users as they scroll past several posts they don’t care about. Any less, and someone who might be interested won’t run into the community in all.

With my communities, that’s about every four to six hours, but I don’t post to each one that often even. And bigger communities with their higher average vote-counts, or more popular individual posts, will have more staying power.