Coding Horror: A Question of Programming Ethics

I'd say, ALL sites should stop asking for username and password from other sites (which they don't control[1]).

It's bad when you get screwed, for obvious reasons. It's also bad when you don't get screwed because it reinforces your false sense of security in an inherently insecure practice.

[1] I don't mind as much about situations like logging in to Youtube with your Google credentials since I know google controls both sites.