I'm not sure if this has been covered already so forgive if it has. Whenever I come on the site I usually click "Show unread posts since last visit" to get the latest posts. I've noticed that as of late this returns a "No unread topics found since your last visit. Click here to try all unread topics." as the result even if I haven't been on in days.
Clicking to try reading all unread topics leads to the same thing.
Which OS and browser are you using? I'll need to try to replicate the issue. I've never encountered it using Linux or Windows 7.
It seems to be working this morning from the office but up til last night it wasn't :S
As far browser/OS combos go I've used it on a few different configurations
Home Desktop OS - Windows 7 Ultimate
Firefox 3.6.26 & 10 , Opera, Chrome
Home Laptop OS - Windows Vista 32 bit
Opera, Chrome
Office Desktop OS - Windows Vista 64 bit
Firefox 3.6.26 & 10, Opera, Chrome