6.5 Set some targets.

You can't know if your app is ``fast enough'' if you haven't defined ``enough''. Is 200 simultaneous users ``enough''? It is for most webapps but it certainly isn't for sites like Slashdot. And, don't forget to consider bandwidth issues. If your users are all in the US or the EU you can generally assume they've got broadband connections. If they're scattered across China... well, you may be lucky if they get a 56.6k modem connected to the net for half an hour a day.