id	summary	reporter	owner	description	type	status	priority	milestone	component	version	severity	resolution	keywords	cc
23430	sanitize_user() disallows + in usernames causes problem for email as username	jb510		"I want to use email addresses as usernames which seems to work fine, except sanitize_user() doesn't allow a + in the username and my email addresses have + in them.  

Google/gmail allows one to use a + modifier on emails like so:
user+admin@gmail.com, user+editor@gmail.com, user+author@gmail.com, etc...

I often use this to get around WordPress's requirement for unique email addresses but it's also intended for and useful in filtering: user+blog1@gmail.com, user+blog2@gmail.com, etc...

Is there a reason we can't allow +'s in usernames or could it be moved to the strict case only?  

See formatting.php:892

"	enhancement	new	normal	Awaiting Review	Users	3.5.1	minor		has-patch	jbrown510@…