You can identify people by their actions, sure. Like "that person who draws those video-games comics" or "that person who knows a lot about kernel development and posts help in the programming threads" (this is a hypothetical person, I haven't met one like that on 4chan yet) &c. But you don't have a name on those usually and even if they do use one, those people only use it to post that content, rather than in general. You don't know if the person is male, female, or a raptor butterfly from Venus.
The threads are also flat and you cannot upvote posts. This prevents the upvote-echo-chamber effect you can see on reddit. If you wish to drown out another opinion, you have to actually post more than the other anon, you can't just call your friends on IRC and have them upvote via puppet accounts or whatnot. And there is an enforced minimum time between posts, which is greatly increased if you attempt to post the same thing twice in a row. Every dissenting opinion is given equal opportunity for being heard (as long as it's not about posting gore pics out of sheer asshattery - that shit gets you banned).
This does sound very unstructured and some kinds of groups do arise, but they're centered around shared interests and not identities. It's kind of strange putting it like that, but 4chan is probably one of the sites on the internet where it's hardest to hurt a specific person. You can post hurtful remarks about some other person's post or opinions, but without an identity to attach to that person, you can't go on to hurt them in other threads. Or even in the same thread in many cases. Now, there are people on certain boards that voice general opinions that will hurt you and make you angry. I suggest posting right back at them.
4chan's design won't work in all cases, though. For instance, StackOverflow and friends work perfectly with the reddit model. But the point of SO is to get the best possible answer to a question. The point of 4chan is to enable fair discussion (also pictures of cats and porn, as long as it's not porn with cats).
It's a shame 4chan is the only well-known site on the internet using that model. I'd love to see different platforms experiment with fully anonymous posting and no upvote system.
P.S. I'm not moot