Ah, the age old problem of measurement. This presentation has been doing the rounds recently and is a good one [I think the images from 70s sci-fi shows helps]

My two cents on ROI?

• Digital marketing at least has the potential to be measurable in a way that “spray and pray” traditional billboard advertising etc. will never provide (until we get Minority Report style profile recognition stuff, but in my mind that counts as digital marketing)
• Organisations still don’t get how Social Media impacts across all areas of their business. They predominantly seem interested in digital marketing results, eCommerce and click through conversions, seldom ever the business benefits as a whole :-(