Unfortunately, web pages come and go. We may have linked to some interesting web page, but the link will not work because this page has disappeared or moved.
Because of this, we sometimes make archive copies of web pages, which we link to. According to accepted practice, such archive copies are allowed unless the owner of a page specifies that archived copies are not allowed by putting a special mark, in the header of the web page.
We will also, of course, remove the archive copy if the page owner asks us to do this.