No offence intended goonie, but I find the user interface of all weblogs plainly inferior to Usenet. Content-wise of course most of Usenet went to hell a long time ago, but there are still pockets of good discussion, useful info, friendly banter, epic flaming, user larting, angst, real erotica, whatever you like.
The tool that makes the key difference for me is Gnus, and in particular scoring. Other people are very attached to other fine newsreaders with comparable features.
Of course, K5 has a kind of scoring, aimed at moderating content, but it is a public system. I didn't know until very recently, but anyone can see how their posts were moderated. This has lead to some unfortunate side effects which I'm sure I don't need to go over here.
However I think the public scoring system may be the worst available system apart from all the rest, that is I am favor of it, and I realise I should do more of it myself to help the common good, but for me, there is a private dimension absolutely missing.
When I am browsing a newsgroup in Gnus, it is the work of seconds to tell the software, in effect, I wish to punish this thread (or author) privately, reduce its score by 10. I can say it's permanent, or temporary, I can match topics using regular expressions, and I can of course add these private scores together ("lower the score of this thread temporarily, apart from when people reply to me"). All this does is affect visibility and sorting, but it's completely private. If I sort by score, the things that I have rewarded float to the top, the other stuff stays there in the middle in case I have a lot of time on my hands, and the stuff I have punished goes towards the bottom. If I have a display threshold some of it may no longer get displayed. If I sort by date I can use bold text and other tricks to highlight high scoring posts.
Whilst every moderation and submission queue vote I make in public is a carefully considered move, helping, I hope, the public moderation strategy that Rusty and co. are trying to launch, my private scoring on Usenet is a fast, sometimes arbitrary tactical move, since I don't have time to read all the worthwhile stuff, let alone all the debatable fluff too. I can temporarily score people down just because their posts are so long and I want to skim whilst my only access is, say, using Palm Telnet, but I might never want them to know, nor would I want anything to be inferred from my actions by others. Alternatively I can permanently send someone to the bitbucket for ever ("If you could post that, then defend it, I never want to see another post by you ever"). Thankfully these are rare, but when you need to filter someone that badly, it's good to be able to do it.
Also when I have a read a topic, it goes away so the next topic with a suitable score comes naturally into view.
Such concepts ("mark as read", "killfiling/scoring") are held to be the standard for a good newsreader. I say we need things like that on K5.