Like one of the other people who's commented here I'm having to multiplely log in to the main site.
I'm on Safari, using 10.4.6. Clicking on links within a section (marketplace, my second life) once I'd logged in seemed to work, but changing sections I had to relog. Closing Safari and reopening an page I'd recently been on forced me to relog even as it said "log out Eloise Pasteur" up at the top!
Loading the page in Camino forced a "would you like to save this password" type message, that seems to have fixed this problem on a couple of quick checks.
EDIT:
It was a temporary fix, relaunching Camino and/or Safari later, no joy - however I did get messages saying I wasn't logged in this time, despite not logging out!