A username is a unique sequence of characters used on computer systems in general and at PS1 as well, of course, to identify a member and to allow them access to computer systems, some computer networks, online accounts and some machines.
Some systems at PS1 use your registered email address as the username to login, such as the Wild Apricot driven member management system.
Most systems, like the computers around the space, the wiki and some others, use a one-word username you selected at some point.
During the transition from ps1auth to Wild Apricot, you will have two usernames, (which MIGHT be the exact same but are not required to be the same) one which you selected when you created your Wild Apricot member profile and one that is in our current Active Directory servers, driven by ps1auth
Your PS1 username might have been established (2018 and earlier) using the web 'members' site at http://members.pumpingstationone.org As of 2018, access to computers around the space is still driven by ps1auth tied into an Active Directory server, that is not part of the Wild Apricot member management system. You can reset your password for [old] usernames at members.pumpingstationone.org
To get access to computers (and computer-connected stuff like the lasers, ShopBot, CNC plasma cutter, etc) you will need a username and to get it you'll need (as of November 2018 anyway) go to members.pumpingstationone.org and click the ACTIVATE link to get that taken care of. The username created and tracked by Wild Apricot is different, unrelated, not connected to this task.
Wild Apricot transition
After 2018, a username might have been established as a part of new account creation or account migration to PS1's Wild Apricot-managed member management system at the newer 'membership' page http://membership.pumpingstationone.org
The username that is managed through Wild Apricot (2018 and later) is not being used for any member-facing applications right now and instructions have not yet been published for password recovery. Email firstname.lastname@example.org and email@example.com for assistance.
You don't need or use a username to access the wifi at PS1, and passwords for wifi are provided inside the space, usually stenciled on the ceilings.