That goes back a few years!
There seems to be a core of players who still use it based on the slow but steady traffic on the Empire Yahoo group. I don't play Empire, I joined the group to discuss "Chef de Batallion" .
The re-launch of Empire (often called Empire V) and Todd Fisher's Revolution and Empire have both come out since but not really made much impact. I think they are too complicated/simulation based for the current fashion which seems to want simpler, quicker Napoleonic games like Black Powder and such.