I had recently noted that ther was no logout button. Adam replied in regards to the administrative site which does in fact have a logout button. I, however, was referring to the new interface which does not have any means of logging out...at least in mobile mode using Chrome / Android 4.4 on my Galaxy S5.
Gary, I think I see what you are saying. It looks like when you are on a small device the header area (with the logout link) is not sizing properly. We’ll look into getting this fixed, but a workaround for now is to simply zoom out (pinch-inwards) when you want to logout, and the links will then be displayed again.