It's just troll heaven.
I know it's common to a lot of sites (eg. the Guardian's Comment is free aka censorship is free) - but here, where it's only recently come into being it simply confuses things and is massively open to abuse
For instance, there's a very sane, interesting poster who has registered in good faith, let's call them user 1234567. Then there's a user with shall we say rather outre views - it's taken a while to get used to the fact that user 9876543 isn't user1234567 (and I've seen people caught out confusing the two).
And now there's a complete troll thread in relationships, started by user1235467 - i.e. almost the same number I'd got used to as being a real poster who makes sensible contributions, but not quite.
Please get rid of this glitch in the system - make people choose user names rather than issuing default numbers.