>so that one email address still can't create multiple accounts?
You can not do that. You have no way of knowing how my mail server handles username portions of the address. Maybe bob+123@ is the same account as bob@, maybe it isn't. It is entirely up to the mail server to decide what it wants to do with it. And likewise, you have no way to know any other username portions are not the same account. I can set my email server up to use "x" as a delimiter, and make bobx1 and bobx2 both go to bob if that's what I want.
You can not do that. You have no way of knowing how my mail server handles username portions of the address. Maybe bob+123@ is the same account as bob@, maybe it isn't. It is entirely up to the mail server to decide what it wants to do with it. And likewise, you have no way to know any other username portions are not the same account. I can set my email server up to use "x" as a delimiter, and make bobx1 and bobx2 both go to bob if that's what I want.