[DanielBryars]

FYI: On the login, it tripped me up a couple of times because the username is case sensitive. There is a tradeoff between security, useability, and support requests; the input is labelled email, and email addresses are usually not case sensitive (and as email addresses used as email addresses are never case sensitive) so it confused me.

[oneeyedpigeon]

TiL. I always assumed emails were case sensitive, and doubly so if used as a username. I find it strange that you even discovered this 'wrong' behaviour on the site in question: you purposefully typed your email address with different casing when logging in vs. registering?

[ReallyOldLurker]

"I always assumed emails are case sensitive"

Wikipedia has a good summary on what is valid. https://en.wikipedia.org/wiki/Email_address

From the second paragraph:

Although the standard requires the local-part to be case-sensitive,[1] it also urges that receiving hosts deliver messages in a case-independent manner,[2] e.g., that the mail system in the domain example.com treat John.Smith as equivalent to john.smith; some mail systems even treat them as equivalent to johnsmith.[3]

You'll find the footnote links at the Wikipedia article, I'm not going to paste the here. So yes, if my email address is my username, then I would expect it to work the same in uppercase or lowercase. If my username is "like an email address, but not an email address" then you make the rules for your site.

[sam_goody]

I have never had a email server be case sensitive, and often use that for mail filtering: myuSer@ - the big "S" is for spam!

In line with with that, I would expect the login to not be case sensitive when it accepts an email.