RFC5322 allows the usage of + in e-mails.
Some mail services interpret + such that all mail that is sent to user+foo@example.com,
user+bar@example.com ends up in user@example.com 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.
- bouyguestelecom.fr
- chevrolet.com
- darty.com
- dicks.com
- endomondo.com
- enedis.fr
- esurance.com
- experian.com
- impots.gouv.fr
- interflora.fr
- jd.com
- jobvite.com
- kobobooks.com
- leboncoin.fr
- libertymutual.com
- live.com
- meetup.com
- net-entreprises.fr
- orange.fr
- oscaro.com
- pornhub.com
- stablehost.com
- transunion.com
- vk.com
- wechat.com
- xiami.com