Today at work, I was searching the web for a semi-reasonable regular expression that I could use to validate email addresses. I say “semi-reasonable” because an RFC 822 compliant regular expression would be quite long. What led to the search was a user with a single-quote (‘) in their address. Damn the Irish.
Anyways, the point of this post is that in looking for a solution, I came across the concept of address tags:
Some mail services allow a user to append a tag to his email address (e.g., joeuser+tag@example.com). The text of tag may be used to apply filtering and to create single-use addresses.
This is a revelation. It makes filtering your email easier and potentially more useful.
At first, I thought you could use this to fight spam, until I realized that people could just figure out that they could remove the tag. This is a bummer. Plus, a lot of sites will probably not recognize and email address with a + as a valid address. Still, it’s worth a try. Slap a tag on your address the next time you give away your email to some random site. If you start getting spam addressed to that address, you know for sure who gave it away.
According to the Wikipedia article, a lot of email services still don’t support this feature. Luckily for nerds, Gmail fully supports it. I even tested it this afternoon. Give it a whirl.