Something I noticed just now:
Super-superficial note: I think you mean "pleas" rather than "please" in the title. (I was confused for several seconds by this.)
Firefox under Linux at home also doesn't show the conversations icon or do anything if I click "login". I knoiw that no cookies are disabled on this. I have to use Chromium in order to get it to work.
Maybe a bugzilla to report bugs? Reporting bugs here or on intercom is suboptimal.
We have a Github: https://github.com/Discordius/Lesswrong2/tree/devel
Adding to the Markdown parsing comment: if we're going to type in Markdown anyway instead of having a proper WYSIWYG editor (make no mistake; I prefer the former!) (Although I see that highlighting text causes a WYSIWYG panel to open up, which I think is excellent), I think it makes sense to separate the raw input from the formatting. I would prefer a system such as Reddit or Stack Exchange have, where the text-box shows the raw Markdown, and the resultant formatted text is displayed elsewhere for review. Combining the two into one area makes fine editing more difficult.
I'm inclined to believe that this would also go some way toward fixing Jiro's underscore issue, since "[struggling] with a malicious parser" is somewhat easier when you have easy access to the parser's input and output. It might not help as much as I think, though, and it would indeed be easier not to have to struggle. (Jiro, as a workaround I would recommend surrounding the offending text with backticks, e.g. `expand_less`.
Also, I'm still having trouble reading this. It's only working on Chrome. Firefox has formatting problems; certain icons (search, "expand(underscore)less", "expand(underscore)more", "navigate(underscore)before", "navigate(underscore)next") show up as text instead of as icons. IE looks good but doesn't show the conversations icon and doesn't do anything if I click "LOGIN".