It started this afternoon when all the extra inbox stuff was going on - I tried looking at MN on various browsers because I was -=-bored at work-- purely in the interests of research and every time I openened a new one I had to log in again, even though I kept ticking the 'keep me logged in' box.
Now I can stay logged on in Firefox and Safari on the iPad and on the mobile site on the iPhone (though that has gone to text only) but Chrome & IE log me out every time I close them.
This is annoying because Firefox doesn't like our Exchange email, which means I have to use IE at work, so I can quickly switch from MN to my emails if anyone comes in....