How long do you notify others (system, people) that the resource is 410 GONE?

[karlcow]

It is not necessary to mark all permanently unavailable resources as "gone" or to keep the mark for any length of time -- that is left to the discretion of the server owner.

http://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-15#section-8.4.11

On a window shop, you might see sometimes a bankruptcy notice. How long the note will be there is dependent on the owner of the building who will be renting the space to someone else at a point.

A shop might put a sign for a product that it is out of stock. Not available anymore and that there will be no more. The motivation for keeping it around or not depends on the people asking for the product, and/or the need for space from the shop owner.

[olivierthereaux]

See also: https://github.com/karlcow/webarch/issues/5#issuecomment-1763866