- What it is
- A short string you type into a login field, plus the written note that records the single place that string is used.
- How you get one
- You invent it before registering, out of material that has nothing to do with you, and then you use it once.
- Where to keep it
- In the same physical record as the rest of your account material, on a line that names the site it belongs to.
- How it goes wrong
- The day you type it into a forum, a chat client, an exchange or a second market, it stops being this.
- What fails without it
- Anyone reading two places at once can lay your two histories side by side and treat them as one person.
- Time to acquire
- A few minutes, most of it spent resisting the urge to pick something you are fond of.
The string, and the record that goes with it
A handle on its own is not the artifact. The artifact is the handle together with an honest account of everywhere it has been typed. Most people can produce the first half instantly and cannot produce the second half at all, which is the problem in miniature. If you cannot say where a name has been used, you cannot say what it joins together.
So the object you should be holding is a line in a written record. Site, handle, and the date you first used it. That is the whole thing. It sits alongside the passphrase and the recovery material in the same place, because the three of them are only useful together.
What a reused handle joins together
A name reused across sites is a join key. It does not leak anything by itself. It lets someone else combine two piles of public writing into one pile, and the combined pile says far more than either half did. A market handle that matches an old gaming account gives away years of timestamps and a rough time zone. One that matches a forum account gives away a writing style, a set of interests and often a country.
None of that requires anyone to break into anything. It requires a search box. This is why the handle is the cheapest item in the whole inventory to get right and one of the most expensive to fix afterwards, because you cannot unpublish the places it has already been.
Picking one that carries nothing
A good handle is boring, pronounceable enough to retype, and carries no information about you. Two unrelated common words work. So does a word plus an arbitrary digit or two. What matters is the source: it should come from somewhere outside your own head, because the things you invent unaided tend to circle back to the same small set of references you have used before.
- Sources that carry nothing: an open page of a book you do not own emotionally, a word list, a dice roll against a printed list.
- Sources that carry a lot: pets, bands, birth years, old email prefixes, the name you use anywhere else, anything you have typed before.
- A handle that is a joke you would explain to someone is a handle you have used before or will use again.
Signs yours has stopped being single use
The name itself cannot be compromised in the way a passphrase can. What degrades is the claim that it lives in one place. That claim degrades quietly, usually because you reached for the familiar string while half asleep on an unrelated site.
The check is boring and takes a minute. Look at your written record. If the line under the handle has grown a second entry, the artifact has changed from a single use name into a join key, and the honest response is to treat it as one from now on rather than to pretend otherwise.
What a login form asks for first
Order matters at the door. A login form asks for the name, then the secret. If you have the secret and not the name, the form has nothing to work with, and no amount of certainty about the second half will get you past the first. That is why the handle is the opening item of this stage rather than an afterthought.
It also travels differently from everything else here. A passphrase is yours alone. A handle is displayed to vendors, printed beside messages and quoted back to you in the order record you keep. It is the one piece of account material that other people see, so it should be the piece that says least.
Questions that come up
Can I change a username after registering?
Most markets do not let you, and the ones that do usually keep the old name attached to your order history anyway. Treat the choice as one you make once. If the handle you registered with is one you have used elsewhere, the practical response is to note that in your written record so you know what that account is joined to, rather than to assume the join can be undone later.
Does a random string of letters make a better handle?
It is harder for a person to remember and no harder for anyone to search for, so the gain is small. What matters is that the string has never appeared anywhere else, not that it looks scrambled. A handle of two ordinary words that exists in exactly one login form is doing its whole job. Legibility helps you retype it correctly on a slow connection.