tip: "uchiha sasuke/uzumaki naruto" angst kudos>10
"The character limit for comments was previously set to 4,300 characters -- a nod to the limit on LiveJournal, where many AO3 coders and users came from in the early days. But that was a long time ago, and some people like to leave much longer comments, so we've increased the limit to 10,000 characters." -- As someone who has become kind of known among her friends as "someone who likes to leave much longer comments," I am thrilled by this development. Had no idea it was related to the old LiveJournal limits! Happy to leave that in the past.