I use the firefox plugin pentadactyl for firefox, which adds a vim-like structure to firefox. One nifty feature I found the other day is in textboxes you can use ctrl-i to open vim and on saveclose it applies what was in the file to the textbox... Sadly I can't figure out how to get the textwidth to not default to 78 (Resulting in the funny formatting you see here).
I've modified my vimrc to tw=0 which seems to have no effect. The issue is not unique to Pentadactyl, the tw setting is applied to 78 on any text file I open it seems.