There's a difference!

[nekoro]

For heaven's sake people, you're giving me an email address with letters and numbers! If you say "oh" I'm going to assume that it's a letter, not a number. The number is "zero."

I can't count the number of times someone has gotten mad because I put 0 when it was supposed to be o, and vice versa. Say the stupid character you mean!!!

[Midnight12]

this is why when saying my e-mail or phone number I SAY Zero or O instead "oh" in general
that makes it that much harder since E-mails are Case Sensitive.