(At the very least, they ought to learn not to assure everyone performance will be greatly increased... just say something like "this is another attempt to increase scalability" (or capacity or whatever) and don't get peoples' hopes up - most people won't understand what's going on in the background, they'll just see "Well, last night they posted that they were improving performance, and today it's just as crappy as ever, so they're lying bastards, or maybe just incompetent", when that's not true. They're actually fairly clueful, they just have a habit of setting user expectations too high.)
Well, they've finally put in place an improvement that'll scale up just as quickly as the site does itself - they've cut their images over to Speedera. I think this is great news - we've used Speedera for years at CCI and while the hardcore do-it-myself sys admin part of me chafes a bit at admitting to it, life's a lot easier and things go a lot more smoothly when you're using a CDN like Speedera (or Akamai or whoever).
It's worth noting that this won't do a thing for the dynamic page rendering, that'll be as slow as ever, but at least from now on userpics (and assuming they've cut them over, stylesheets, site images, and other similar static content) should be consistently fast and reliable. (And any site delays from problems on that end will now go away, pretty much 100% of the time - Speedera's pretty good at what they do and they've got a lot more capacity than LJ will use anytime soon.)
Now they just need to figure out how to get the dynamic stuff working well. :)
Update: Heh, they're adding a netapp so they'll have more capacity for hosting userpics and other images. Hehe. They're starting to sound sort of like CCI. ;)