I haven't actually tried this, but looks like it would work. One should note that it doesn't remove the ability to crosspost. It just removes the button.
Originally posted bytxvoodoo at Fixing LJ's new "connect" twitter/facebook thing
If you don't like LJ's new "share on fb/twitter" thing after comments etc, (see latestnews post), there's a Firefox* solution via Greasemonkey: "Disconnect for Greasemonkey"
*Apparently, greasemonkey scripts from userscripts.org can be used by Chrome via Chromium - see here for more info.
ETA: this script was created bydaluci
Son of ETA: If you use Safari, check out this link on how to use Greasemonkey scripts w/ safari. (Here's a SIMPLE tutorial on how to install and use it)
Grandchild of ETA - if you installed the script before,daluci has updated it to include editing comments and other comment pages :D