Jonathan over at OptimizeandProhesize.com has a greate post on the Web Analytics Industry and multiple metrics: "Trying the find one or two metrics that can be the “Digital Nielsen” is just plain stupid. Digital is not like other media. For starters it is user controlled. Also, it is far too fragmented a medium for standardization to be helpful in understanding results. There are and should be multiple metrics used to gauge success in digital. The key is not dumbing down the metric (and thus the value of it) but determining when and where to apply appropriate metrics to answer the same two questions -- how much did I spend and how much did I make?
Here’s a snapshot of five challenges in creating standardized metrics:
1. Success metrics need to be different for publishers and advertisers 2. Success metrics vary across display, search, social and site 3. Success metrics can and should vary by vertical 4. Success metrics need cross-media attribution 5. Success metrics within media vary based on the platform"