Being First Is a Moat

Simply being first isn't the moat -- _switching cost_ is the moat. You've got to get people using your app in order for being first to matter. And the easier it is for those users to switch, the smaller the moat is.

IE6's moat wasn't that it was first at anything, it was that it was installed as the default browser on all new Windows machines -- switching was work. And once lots of custom web applications were built that used IE6-only features (or required IE6-only bugs), switching became impossible.