As far as I know, it's like this:
Threads |
no expiry date, irrespective of level of membership |
Games |
retention period of 30 days for basic members |
Messages |
retention period of: ??? for Basic members 42 days (Gold membership) 1 year - Diamond/Platinum |
However, in practice, threads can disappear for a number of reasons. For instance:
The originator closes his account or gets banned. |
The thread gets too large (a few thousand posts) and becomes corrupt. (In any case, you can't view more than 100 pages.) |
The thread become controversial, inflammatory, abusive, etc. and gets deleted by staff. |
Also, if chess.com disappeared, everything would go with it - as the people at ChessPark.com discovered recently. If there's a thread containing information that you don't want to lose, make sure you keep a copy.
Someone enquired recently: How long do threads stay available on this site? Will there ever be a situation where a thread is no longer accesible to be viewed?