i went to the twitter web site and quickly determined that there wasn’t a way to connect with a tech-support drone who had any hope of giving me a cogent answer to my (primarily twitter-related) problem – one of the reasons i was so hesitant to get wrapped up in this whole thing to begin with… 8/
anyway, i went to the #kubuntu IRC channel on freenode and met up with someone who, once he had seen the picture of the dialogue box, had the idea that it might be a gnome dialogue, which is odd, considering that i am running KDE. admittedly, i do have a few gnome applications installed (synaptic, for example), but as far as i know, none of them are using the gnome-keychain application from which this seems to be a dialogue box, so he suggested that i remove it, which i did.
after logging out and logging in again, it looked as though the dialogue had vanished (a good thing), so after waiting around for half an hour or so, i quit the IRC client.
almost immediately the authorisation dialogue came back… 8/
i then began shooting down processes that looked suspicious, starting with anything even remotely gnome-related. eventually i shot down enough processes that my system became unstable, so i had to completely shut down the machine and restart.
at this point, the dialogue hasn’t come back yet. i’m not sure whether it’s because of the fact that i removed software, or whether it’s because of the fact that i hadn’t actually shut down the computer, or if it’s because both of those things happened… at this point, i’m not completely convinced that the dialogue won’t come back again.
ETA: it’s back… 8/
another thing i learned about was the existence of yet another browser, rekonq, which has some interesting quirks and probably won’t replace firefox any time soon, but it’s an interesting addition to the collection.