It's an archive of websites taken in snapshots. I know that anyone can have a webpage archived there by using the Wayback Machine site's tools, but I'm not sure if there are instances where it archives websites/pages automatically. @Ken Anderson is more conversant in it than I am.What is the Wayback site?
There are lots of snapshots of Seniors Only Club there that you can browse/search just as though you were on a live site...you just can't post there. The site says that SOC has been saved 4,786 between Feb 6, 2015 and today.
Here is the link for the SOC archive: link