“+” is a valid character in an email address, idiots!
It’s 2010 and there are still developers out there who don’t know which characters are allowed in an email address. The “+” sign IS a valid character! And I use it! Regularly!
Whenever I have to sign up for something, I usually use my gmail address. Gmail is nice enough to route an email like firstname.lastname@example.org to the same inbox as email@example.com. This allows you to “tag” emails and figure out who sent them. If I were to signup for myspace with firstname.lastname@example.org and myspace decides to sell my email address for some ad-campaign, I could easily find that out.
However there are tons of places (facebook pictured above) that do not know that “+” is allowed … argh!