Where this is more subtle, however, is when you sign up for a new online account somewhere (say ... macosxhints.com?) and receive your email containing your username and password. You type in your username, but because the password is a randomly generated string of gibberish, copy and paste is the obvious method of choice. You paste the password, hit login, and get "Sorry, wrong password!" So you try again, it fails again, you get frustrated, you ask the system to send you a new password (using a lost password email option), and that one too fails. So then you write the site admin (say ... me?) all frustrated and upset that the site isn't recognizing your new password.
I have received a bunch of emails that basically follow that described chain of events, and it took me quite a while to figure out what was happening. So until Apple updates Mail.app to fix this glitch (please tell them about it!), I highly recommend that you hand type every password you receive in Mail ... for your sake, my sake, and the sake of probably many other frustrated webmasters out there!

