Looks like there’s an interesting bug which is doing odd things to comments. I’m not seeing it, though; but if you are, let me know! Thanks (: We found the bug – it only appears if you display related posts. Updating to version 22.214.171.124 of the plugin will fix it. (I’m pretty sure I fixed a bug in the AJAX tag-adding bits too – it looked like it would have been broken, in any case)
Sometimes you take steps forwards, and then you take steps backwards.
In the WordPress 2.0 version of the plugin, I’ve moved the tag-entering bit back to how it was previously – the way I had it, to get it to work was a flakey-flakey thing which caused problems which far out-weighed its usefulness.
I’ve updated the help (I think!), to include the last few versions worth of changes.
And fixed a few other bugs here and there (: