Conversion rate
The number of visitors who buy something.
Purchases per year
The number of purchases made by each customer per year.
Average shopping cart size
The amount of money spent on a purchase
Abandonment
The percentage of people who begin to make a purchase, and then don’t.
Cost of customer acquisition
The lifetime value of each customer.
Revenue per customer
The lifetime value of each customer
Top keywords driving traffic to the site
Those terms that people are looking for, and associate with you a clue to adjacent products or markets.
Top search terms
Both those that lead to revenue and those that don’t have any results.
Effectiveness of recommendation engines
How likely a visitor is to add a recommended product to the shopping cart.
Virality
Word of mouth, and sharing per visitor
Mailing list-effectiveness
Click-through rate and ability to make buyers return and buy.