I've always found the Amazon approach interesting. As part of their sales funnel they email related content to you based on your browsing habits when logged in. Clearly they therefore have a large incentive to persist the user's login status.
Their logout link takes the form
"Hello %NAME%. We have recommendations for you. (Not %NAME%?)"
'Not %NAME%' is the logout link, which confuses the hell out of users (just Google 'Amazon logout'). Even if you know it's there, you battle subconscious friction in clicking that link when it is in fact your name.
This strategy has been around years and no doubt adds visibly to their bottom line, even while it exposes users to potential fraud issues with others using their account for one-click purchasing.
Most of the time, Amazon considers you to have a "soft" login. Want to view your order history? Password please. Change an order? Password. View/update addresses/credit cards? Password. This is sometimes irritating to the user, especially when clicking the "where's my stuff" link from an Amazon order email, but it serves Amazon well in that they can trace most site actions to a user account while at the same time maintaining an acceptable level of account security.
Sometimes (I believe), you will even get a password prompt for a "one click" purchase. Even if you don't, your one click purchases can only be delivered to a previously configured address, and to add a new address requires entering the credit card number again, and, of course, your password.
I find it less intrusive than Linkedin's soft login, which really annoys me, especially as I cant remember my password often. You can go as far as writing someone a message, then you need the password. If I can read my private messages, surely I am good to send one?
Amazon seems to be testing a new homepage design which is a little different. It actually has a drop down menu on the right side which includes "Sign Out" link. It also doesn't have the normal left side department navigation nor the welcome message as stated above. However, it still remembers you.
It seems like they are gathering statistics on this new format as I couldn't get back to it after signing out.
Their logout link takes the form "Hello %NAME%. We have recommendations for you. (Not %NAME%?)"
'Not %NAME%' is the logout link, which confuses the hell out of users (just Google 'Amazon logout'). Even if you know it's there, you battle subconscious friction in clicking that link when it is in fact your name.
This strategy has been around years and no doubt adds visibly to their bottom line, even while it exposes users to potential fraud issues with others using their account for one-click purchasing.