January 1970 is a legacy date, it's got a proper name but can't remember it. It is the date that computers keep the time from and if a date is not shown then it defaults to that. I had this when I moved my old forum to
vB. It was caused by the different ways the two software packages datestamped messages in the db. The
vB staff modified the import script and that fixed most of them, but many inactive members still have that date in the db.
Have you migrated software at all?
Bob