DR Jane - As for your Facebook inquiry...
If you're talking about your Facebook Chat log, well... The Chat function normally keeps all of your "conversation(s)" until you clear it. However, I think there may have been a purge of sorts over the past day or two when they made the permanent switch to the "New Facebook".
Now, if you're talking about messages you've sent back and forth, well, those should still be in your Inbox.
And if you happen to be talking about something else, well...

