Use Gmail to Generate Unlimited E-mail Addresses

Use Gmail Generate Unlimited E-mail Addresses:

"Gmail has an interesting quirk where you can add a plus sign (+) after your Gmail address, and it'll still get to your inbox. It's called plus-addressing, and it essentially gives you an unlimited number of e-mail addresses to play with. Here's how it works: say your address is pinkyrocks@gmail.com, and you want to automatically label all work e-mails. Add a plus sign and a phrase to make it pinkyrocks+work@gmail.com and set up a filter to label it work (to access your filters go to Settings-->Filters and create a filter for messages addressed to pinkyrocks+work@gmail.com. Then add the label work).

More real world examples:

Find out who is spamming you: Be sure to use plus-addressing for every form you fill out online and give each site a different plus address.

Example: You could use
pinkyrocks+nytimes@gmail.com for nytimes.com
pinkyrocks+freestuff@gmail.com for freestuff.com
Then you can tell which site has given your e-mail address to spammers, and automatically send them to the trash."

I found out about this at another site that was talking about using the + tagging to get emails to automatically forward to your Evernote email address by creating a filter in Gmail... this post (linked above) offers some additional ideas for using this feature in Gmail.

One of the commenter's on this post mention that you can ALSO use periods (.) in your email address and it will still get to your account, because many sites that offer subscriptions may not allow adding a plus sign to an email address.

Pretty cool stuff with nearly endless possible use cases!