kuro5hin.org is discussion website which is using some similar UI ideas as, for example Slashdot.org uses, maybe since it once upon a time was based on slash (the software which makes Slashdot run). However, Kuro5hin's admin and founder Rusty rewrote the whole backend software from scratch (also in Perl) and called it scoop.
The name Kuro5hin originates from a pun on Rusty's name (rusty == rust == corrosion == Kuro5hin), the "5" was inspired by the character "Da5id" from Neal Stephenson's Snow Crash.
Whats somewhat original about the site is the whole moderation system. If a registred user has submitted a story it is placed in the submission queue. Then any registred user may (and should!) evaluate it and vote if either:
- the story should be posted on the front page (+1 FP)
- the story should posted in the according section (+1)
- the story should be ditched because it's crap and/or poorly written (-1)
- the user doesn't care about the fate of the story (0)
This way the score accumulates a score over time, either positive, or negative. Upon reaching a certain threshold the story is either posted or ditched. While the story is lingering in the queue, users already can post comments, and sometimes a pretty lengthy discussion is already taking place while the story hangs in the queue.
The whole power hierarchy is flatter than on Slashdot or e2. There's just admins, editors, and normal registred users.
Comments are rated, again, by all registred users, <sarcasm>not just by some selected few who have proven their eloquence by hanging around for long enough time.</sarcasm>. The only privileges editors have above normal users is the ability to edit stories, such as fixing typos, and rating comments to 0 (which marks them as spam and thus will be hidden)
Another interesting feature of K5 is "hotlisting" of stories. This will place the title in a box at the frontpage and you'll always be able to keep track of new comments, as long as you want. This leads to both the focus of Kuro5hin and the difference between it and Slashdot, the first is mainly discussion oriented while the latter is mainly news oriented.
While most users fetch from Slashdot their 3-times-a-day newsfix, and drop the occasional line if something really touches them (unfortunately, often without reading previous comments), Kuro5hin's audience definitely spends more time with reading the story, the comments and preparing their share. Of course, this also reflects in the type of posted stories and the posting frequency.
Many K5'ers think of their communtiy as superior to Slashdot. My personal opinion is that there are unfortunately and definitely more trolls, spammers, nitwits and idiots around on Slashdot, as you can often see from the comments. While most comments on kuro5hin are well written and well thought of, Slashdot's comments are often "funny" one-liners and only worth a read if you set the rating filter to 3 or even 4 (Kuro5hin doesn't have any feature to hide comments, except 0-rated spam, and thankfully, it isn't necessary either).
Most factual info about Kuro5hin taken from the Kuro5hin faq (http://www.kuro5hin.org/special/faq)
On the other hand, Slashdot does have a much larger audience, and of course this also brings more trolls to the page. Thus, maybe because of the lower count of trolls, Kuro5hin's editors have it a bit easier to nail them down. Well maybe.
For my part, I'm visiting both sites frequently, but I suggest you to judge for yourself.