Internet Marketing Formula
Effectiveness = (Impressions of site/Searches) X (Clicks or Visits / Impressions) X (Sales / Visits) X ($ / Sales)
(Copyright Daniel Crean - registered with United States Copyright Office)
This was developed as an analogy to (and was inspired by) the DuPont Formula fron finance.
Return on Assets (=Net income/Assets) = (Income/Sales) X (Sales/Assets)
Return on Equity (Profit/Equity) = (Income/Sales) X (Sales/Assets) X (Assets/Equity)
All these formulas are exactly true. They are identities and not matters of opinion.
But defining each of the factors is harder. And the how to affect the factors is the really hard part.