I think the problem the OP was describing is that the titles vanish too quickly to be readable - this is an old, well known bug in Firefox. In addition, Firefox doesn't wrap long titles - it truncates them (at 23 characters, I think). The LongTitles add-on addresses both of these problems. I wasn't able to view popup ALT text reliably on any web pages until I installed it.
My current version of Firefox -- just installed and all new and shiny -- won't even install LongTitles; it says it's intended for older versions, and that the bug has been fixed. Well. Isn't that special.
Re: Titles in Firefox
Re: Titles in Firefox
Re: Titles in Firefox