AHN: What can we learn from Reddit?

In only the past couple months, the bottom seems to have fallen out, and to me (as someone who used the site for the past year) it's become virtually unusable. At this point, there's very little reason to use Reddit over sites like Digg unless you're reading comments on marginal topics that draw little interest.

So, the question is, what can we learn from Reddit? There was a bit of a false start the other day when somebody suggested making this a walled garden, which is clearly the wrong thing to do. What we need to do is determine the best ways to discourage thoughtless, asinine members and make the site distasteful for them without sacrificing the needs of the users we'd like to attract. I think we all agree that sites like this one fill a valuable niche, so we need to market to _only_ that niche.

* Mere exclusivity is not the answer, as evidenced by the poll results from the aforementioned post.

* Being abrasive would be in the wrong spirit as well, and would be tedious (we don't want to become moderators in that way).

I'll start: A simple option is to require a nominal signup fee to post. I'd be for it, although I'll admit that it's contrary to the "hacker" moniker which suggests anonymity (and doesn't much reflect the nature of the community, in any case).