A lot of people know this already, but I’ve seen a few blank faces when I mention it in real life1, so I thought it’s worth a mention.
The gist of it is, joeschmoe@gmail.com, joeschmoe+purchases@gmail.com, joeschmoe+XYZ@gmail.com will all be received by the address joeschmoe@gmail.com, where XYZ is anything alphanumeric. This is very useful because you can filter on the “To” address, which makes it very specific.
So you can use joeschmoe+paypal@gmail.com for your Paypal account, and have a 100% accurate filter for any e-mail from Paypal, no matter what its subject, contents, or From address is. Plus if they ever sell your address to spammers, you would know.
There are lots of possibilities, so try what works out for you. You can have a specific joeschmoe+amazon alias, or register for multiple online stores with a joeschmoe+purchases alias.
If you do this with a brand new e-mail address and never give out the base local-part, you can constantly maintain a zero message inbox, with every incoming mail perfectly filed.
One caveat: not all sites obey RFC2822 to the letter – some of them disallow plus signs in the local-part (I suspect that most times this is not intentional, just incompetence—since it is much easier to copy-paste the canonical e-mail regex than roll your own).
PS. If there really is someone out there using joeschmoe@gmail.com… Mr. Schmoe you have my profound apologies.
1 You know how it is: you’re in a crowded bar, and some beautiful girl comes up to you and goes, “Excuse me, would you happen to know a more efficient way of filtering my e-mail?” while licking her lips slowly.
