Latent sales and who gets the credit
The Web Analytics Association has published a set a of important definitions of web analytics terms to “Promote Consistency across the Rapidly Evolving Web Analytics Community”. Standards are good and everyone benefits if practitioners and analytics vendors “speak the same language”.
But do realize that tools will still be different in many ways and will continue to have different underlying assumptions. John Marshall recently enlightened me about a specific case:
Many products have long sales cycles involving multiple visits prior to purchase.
Did you know that by default ClickTracks credits the first referrer for the sale, whereas Google Analytics credits the last referrer? Omniture apparently can attribute credit across a number of referrers. Dennis has a great post about the WAA definitions; Dennis: how does IndexTools attribute sales?
This is not to say that one approach is necessarily better than another, but try to find out about these kinds of assumptions underlying your web analytics program.