amazon does that. you can browse the site and it identifies you and your preferences, but when you go to check out or modify account settings, you have to enter your password.
... and it feels really natural. Amazon identifies me easily, but if I do anything that feels like I need my password, it asks for it. Apple's App Store has similar logic, although it bothers me in one place where they ask for your password when downloading free apps.
And then there's Windows Live. Click on anything remotely related to Passport? You need a password (followed by 17 redirects, which is hilarious when managers have sound turned on and you here the "click click click click click" as IE bounces around).
followed by 17 redirects, which is hilarious when managers have sound turned on and you here the "click click click click click" as IE bounces around
I wonder if someone added a few extra redirects just for that reason. Seems like a quick and easy way to remotely identify coworkers that don't customize or disable their sound scheme and use IE.
I saw one of Amazon's UX team at a talk a while back, and the way he described it is they have a set of actions/permissions for people who are totally logged out, a set for people who are "sort of logged in", and then a set that require full login.
It's definitely tricky to implement (how do you determine whether a user is "sort of logged in"?), but once you get over the conceptual hurdles it's a pretty awesome user experience.
However, I would argue that like much of what Amazon does, it's not necessarily appropriate for the majority of sites.
And then there's Windows Live. Click on anything remotely related to Passport? You need a password (followed by 17 redirects, which is hilarious when managers have sound turned on and you here the "click click click click click" as IE bounces around).