[ianburrell]

My understanding is that Reddit does lots of spam filtering. It does a good enough job that moderators don’t complain about that. It is good enough that can have mostly unmoderated subreddit if don’t care about off topic posts.

The moderators are responsible for off-topic filtering and catching anything, usually human made, that slips through.

[not_alexb]

I've moderated tiny subreddits and I can assure you that spam leaks through everyday.