RFC5322 allows the usage of + in e-mails.

All mail that is sent to [email protected], [email protected] ends up in [email protected] mailbox. This helps managing your inbox, is extremely useful if you want to detect a service that sells user e-mails to spammers and just keeps yourself more secure.

Some services don’t support this practice, though.

Here's a list of webservices that has no idea how to validate an email address properly or just prohibits this feature for whatever reasons.

Hall of shame if you will.

• http://jobvite.com/
• http://kobobooks.com/
• http://meetup.com/
• http://oscaro.com/
• http://pornhub.com/
• http://vk.com/
• http://www.leboncoin.fr/
• http://www.interflora.fr/
• https://www.espaceclient.bouyguestelecom.fr/
• http://www.endomondo.com/