I have participated over many years as a successful BI Consultant, but still the true nature of consulting seems elusive to me.  Simply put, "Consulting" means providing expertise, advice or recommendations to someone else whose responsibility it is to act. Good consultants solve problems for their clients.  Good consultants have some sort of expertise that their clients don't have.

Before going any further let me share a joke about consultants - A nuclear power plant was about to blow, so a consultant was called in.  The consultant came in, punched a few buttons in the control room and the situation was fixed.  When the consultant presented the client with a bill for $10,000, they said, "You were only there for 5 minutes and you're charging $10,000?  That's outrageous!"  To which the consultant replied, "The 5 minutes of my time only cost $5.  Knowing which buttons to push to avoid disaster costs $9,995."