Do you never have enough room to write your comments here, or anywhere for that matter? The Resizeable Form Fields extension allows you to resize text boxes to anything that you want. I’m sure you’ll find this extremely useful on blogs and in forums where it would be nice to see your entire comment without needing to scroll.
It appears to work on almost all of the pages I have tried it with. I have noticed that it doesn’t work, however, on the SlashDot submission page for some reason. I’m sure there are a few other places that it won’t work but you’ll find that it works with many sites.