The document discusses how to use Google Analytics to track revenue from different marketing sources by setting up ecommerce tracking or goals. It recommends (1) tracking referral sources to see who sends visitors, (2) comparing sources using custom segments, and (3) most importantly, evaluating sources based on the bookings and revenue they generate rather than just site visits. The document also provides instructions for setting up ecommerce tracking or goals, creating custom segments and reports, and automating reporting through dashboards, shortcuts, and emailed reports.