[jere]

If you've been developing login systems for any length of time, this should be fairly obvious.

Be careful about taking that "it’ll get bounced" attitude too far though. The last time I did so I forgot to trim the email addresses and didn't lowercase them. Failing to trim will probably result in the email going through, but then might cause problems later on when you try to match their login ID to what they enter the next time.

A similar issue arises for case. Email addresses are supposed to be case sensitive but providers don't seem to take advantage of it in practice. Again, the case a user types varies from time to time (I assumed nobody used upper case... it seems silly). And if you switch to case insensitive login IDs down the line, you may have to deal with duplicate accounts (same email but different case).

[Steuard]

Regarding upper case: I've taken to typing the first part of my work email address as "JensenS". My wife and I work at the same place, and when I wrote it as "jensens" there were honestly people who assumed that address was a plural and went to both of us.

[jere]

>when I wrote it as "jensens" there were honestly people who assumed that address was a plural and went to both of us.

facepalm