It's not using LJ's webpage to post an entry that kills my connection. It's using LJ's webpage to post this one particular entry that does it. Everytime. Takes out Lut's connection, too. Something about LJ just hates this particular combination of characters. And it's not length, because I've posted longer entries. I can post any given part of the entry -- but not the entire thing at once. It's got some html code in it, but I can post all of the entry that contains the coded bits. This is so weird.
I would present it via Semagic, but now even Semagic can't manage it. O.o It's the Evil Entry of Doom, I tell ya! Beware!