When you insert a literal tag in a forum post that has a very long line it breaks the dislay (see explanation below).
An idea to fix it:
Wrap long lines, but put some kind of indicator that will clearly display where a line really ends.
I know that it's not easy to fix this, but would be really nice since this doesn't only break the visual impression of the site but also makes problem for functionality (you don't see the entire text, and have problems with copying it).
P.S. I haven't checked, but I suppose this also happens in blogs and articles.
or look at the attached image.