I really really like reddit because it reminds me a lot of usenet/BBS.
Now you may think reddit is a message board like GAF and it should be moderated and curated but that's really missing the point.
Reddit exists more as a platform. It's like vBulletin on GoDaddy.
Reddit is made up entirely of subreddits. All these subreddits are moderated (or not) but their users. You could make a subreddit today, anonymously, without using an e-mail, and make it about anything you want. You can set karma limits, you can have no karma at all, you can control the discussion -or not.
If you hate reddit, you can make a reddit about dead children, fill it with photos of dead children, and talk about how awful reddit's photos of dead children are.
The "karma" thing is internet points, they really don't matter, you can make a new account anytime you want, you can game karma if you are so inclined, a person with a million karma and a person with negative a million karma with both have their comments displayed equally.
If you don't like someone you can shadowban them where they will still be able to post but no one will be able to see their posts.
The idea behind reddit is that anyone can create any space to discuss any topic and have a platform to do so. And if you don't like those topics you can easily ignore them, or you can find special niche interests. If there was an index of every vBulletin board on vBulletin.com it would look just as horrible, but no one would say we should get rid of that message board software. All reddit does is host all these boards in once place. It really is like hopping onto a usenet server and going down to your subgroups.
As to the formatting, it's just nested comments. Like how old BBS' and usenet used to work. You respond to threads. If anything it's easier to read than GAF because you can follow a conversation at a glance. I can't be the only person who's ever clicked the little circle next to a quoted name because I wanted to see what the quote had quoted?
I just find it nice that there's a place on the internet that tries as much as it can to keeps its hands off self-censorship. The child-porn thing obviously can't be hosted, but reddit doesn't host images, that was imgur and other sites reddit linked to. When sites start policing their content they obviously have to make judgement calls on the margins, but reddit just says they are a platform, and lets things go.
Google's motto used to be "don't be evil" and for the most part they don't censor any information, no one is upset that you can use google to search for reddit to search for dead children photos that were found on google, but google are the guys suppressing searches for Tienanmen Square from Chinese IPs.