Thrasher borrows from the Jason Burby and
Shane Atchinson's book "Actionable Web Analytics" to suggest some KPIs for a commercial site--metrics that are typically tied to revenue. Think about using stats like overall conversion rate, average
order size and the Web site's effect on offline sales as possible KPIs.
Meanwhile, for sites where commerce isn't the primary focus, Thrasher borrows from "Web Analytics An Hour a Day" by Avinash Kaushik and suggests using visitor loyalty, recency, length of visit and depth of visit as your primary KPIs.