The last post before TFL went down was on 12/31/07 at 12:33 AM EST
by Slopemeno.
The first post made when we came back up was today at 9:25 PM EST by mmasteve.
I don't know what time the server went down, so it is possible that anything posted between those times was lost. For much of that time, though, the forums were completely inaccessible so I doubt there was much loss of data.
Hope this helps. P'raps tyme will be along to explain it soon.