I’ve updated the little script I wrote to keep track of which comments are new on LJ and Dreamwidth (LJ now does this automatically in its default style, DW doesn’t, by the looks of it). Thanks to various people for telling me it was broken for HTTPS sites, which LJ and DW both default to these days.
Userscripts.org is long dead, so I’m now hosting it on my site.
I don’t know if you know, but Greasemonkey 4 has broken the script.
Yes, they changed their API and broke the world. I suggest using Tampermonkey instead.