How well does Stack Overflow's spam prevention mechanism work?

Question

So it seems that Stack Overflow's reputation feature is used not only to distinguish members who have put more time into the site than others, but also as a spam deterrent.

Seeing as the privileges of a person with low reputation are extremely limited, and the privileges of an individual with a lot of reputation is vast, I was wondering how resilient this mechanism is to spammers.

Although there is a lot of frustration coming from new users, this mechanism seems to deter spam by preventing new users from posting links and editing posts without peer review. So that begs the question: How much spam does this feature prevent? I know this figure would be hard to estimate but I'm curious.

Furthermore, have there ever been instances on SO when people would pay individuals to farm reputation, that was later used for spam posts?

Edit: I forgot to mention that I'd like to forego the discussion of CAPTCHAs and just talk about the reputation system and its effect on unwanted posts

Answer 1

There's a lot more to the spam prevention than just the limits of reputation. Yes, this does go a long way to helping to cut down on spam, but we have excellent moderators who do a lot of work to delete spam... we have excellent users who will flag spam when they see it, so a moderator can act on it. That's why you see so little spam on the sites. As soon as anyone sees it, they should flag it. And a moderator will remove it.

I am speaking about real spam of course. Don't just start flagging everything that possibly could be spam. Let's keep the signal-to-noise ratio high for our hardworking mods :-)

have there ever been instances on SO when people would pay individuals to farm reputation, that was later used for spam posts?

Because of the way the system is designed, this just isn't possible. Regardless of how much Reputation you have, if you start using your account for spamming, you'll still get flagged and your SPAM will get deleted. If you continue, your account will be suspended, and you won't be able to post anything at all.