Email "Dot-Addressing"

When giving out my email address, I use plus-addresses (foobar+baz@example.com) to create unique addresses that implicitly organize my emails (and if it’s used for spam, trace back who sold/leaked it). Unfortunately not all websites accept + as a valid character and I’ve come up with something I call “dot-addresses” as a workaround.

Even though RFC 822 specifies + as a valid character in the username section of an email address, some websites will reject it. On the other hand, periods in email addresses have become completely ubiquitous, universally valid. Many organizations use a firstname.lastname@example.com format and most email providers will implicitly ignore periods, treating firstname.lastname as if it were firstnamelastname. When plusses are rejected, maybe dots can be used instead. How can we use dots to generate unique, identifiable email addresses? In other words, how can we pack the most information into an email address using dots?

In the address firstname.lastname@example.com we have 15 open positions to place a dot, giving us 2^15 or 32768 unique addresses that we can use. ¹

My strategy is to use my first name for categories and my last name to identify senders. firstnam.e might correspond to “shopping”, firstna.me to “bills”, and firstna.m.e to “social media”. Senders are then given a unique id per category by incrementing the number in the lastname. The first ID is lastnam.e, second is lastna.me, etc. This is just binary of course so the first and last name portions can be converted to decimal to keep track of them easier. I note that 1 → “shopping”, 2 → “bills”, and 3 → “social media”, and I keep track of the current max ID for each category.

This two-part approach is great for filtering because most of the time I don’t really care about the sender I just want it to get categorized correctly.

There are a few downsides to the dot-address strategy:

• It assumes an address of moderate length (but the number of dots between letters could be used.)
• It’s difficult to keep these straight and most website logins will not ignore dots (but you should be using a password manager anyway.)
• Trying to spell a dot-addressed email verbally will get you strange looks at best and be rejected at worst.
• They are not composable, you can’t have two categories for one address:
  overlapping two dot-address categories will correspond to a completely different category. With composition, firstna.m.e in the above example could be “social media” or “shopping” and “bills”. However, if the number of categories is limited to just the spaces between letters you can then have composable categories.

I’ve been using this system for a couple years. These days most websites accept plus-addresses and I’ve only had to resort to dot-addresses a handful of times. But those handful of times, my messages are being organized correctly!