Did you know that you can append a plus sign and any combination of alphanumerics after your gmail address and still get the email? I did and I love the feature.
I use this feature for most of my non-personal email corespondents. For example, if I were to provide an email address to the fictional phone company No Cell Service, I’d give them firstname.lastname@example.org. This provides two key features. First, I can easily create filters to handle mail sent to email@example.com. I can move it to any folder, forward it, mark it as important, or delete it. Second, if I start getting spam emails to this address, I know No Cell Service leaked my phone number, which is easily blockable.
Apparently, many websites don’t know about this cool feature. Discover Card does not accept plus signs in email addresses and they throw up a nice big red message telling me so. Instead I give them a crap email address and forward any email from Discover to my main address. It’s a pain in the ass, but it is what it is.
There are too many companies behind on the times that need to get their act together and start accepting the plus sign. Paint Scratch doesn’t accept the plus sign in email addresses, but they are not nearly as graceful as Discover. While making a purchase at Paint Scratch, they gladly accepted my email address with a plus sign. They sent me a confirmation email to firstname.lastname@example.org. About an hour later they sent me an email saying there was a problem with my order. The problem was that their credit card program couldn’t handle the plus sign so it ignored it and tried sending the receipt to email@example.com. The email bounced because it didn’t exist. Doh! Even if it didn’t bounce, it still wasn’t the correct email address. Double doh!
In conclusion, companies should be allowing plus signs in email addresses as the character is legal. If you aren’t willing to do that, then you need to at least throw an error during input or not automatically remove the plus sign and assume the address will still work.