I was suffering horrible hangs will some sites updated, notably Facebook.<p>On upgrading Firefox to 3.6 I had to edit the install.rdf of the "It's all text" extension to allow it to work. I noticed a comment on the Mozilla add-ons site saying that this extension could be the cause of the slowdowns.<p>Anyway (with the hacked install.rdf) "It's all text" still works in Firefox 3.6 and my slow-downs have gone.<p>Happy! I didn't want to swap to Chrome without "It's all text", noscript and adblock plus.