A user registered with my WordPress blog as “bob.smith+bc@gmail.com”
(for example).
I’m fine with that. However, if the user comes back with
“bob.smith+bc2@gmail.com”, I want to stop him for registering again,
and maybe politely remind him that he’s already registered with the
“same” gmail address.
Is there a plugin that does this?
Same question for things like “bob.smith@gmail.com” and
“b.ob.smith@gmail.com” (using extra dots in the email address, which
gmail recognizes as the same address).
I realize people can easily get free no-registration-required email
addresses, so this won’t stop someone from registering multiple times,
but it might help.