Signing in with an account, a licence key or through the web, taken seats, signing out and the licence states in System options.
The app opens once the computer is signed in and holds a seat in the licence. Signing out frees the seat.
Every licence has a number of seats. Signing in takes one for this computer and holds it until you sign out.
An activation has a validity the app keeps renewing whenever it reaches the server. A computer that is offline for a long time says "This computer's activation has expired" and renews it on the first connection.
System options → Account shows who is signed in and the licence state: active, activation expired, suspended, stopped or not activated. That is also where you sign out — signing out frees the seat and removes the stored key.
Publishing web configurators needs a sign-in with an account, not just a key — a page is published under the company the account belongs to.