The only topics that should be considered "stale" are, perhaps, those pertaining to some kind of dated event, like meteor showers or the best viewing of Mars. There are topics that have had no replies in over a month that are still worthy of being read and responsed to today. The lack of responses is perhaps a measure of the limited readership/membership and nothing more. Interest in string theory and cosmology may have ended in here, but not among the people I see almost daily, as an example.