River ships are smaller that ocean cruise ships. Most vessels on European waterways carry around 150 passengers rising to 3,400 on the Russian Neva waterways and lakes.
River cruises travel by day and stop at night - the opposite to most ocean cruises.
River passengers consider themselves to be on a journey, rather than a cruise.
River cruises are more educational than indulgent. Passengers can sightsee from the comfort of the ship.
Rivers are national thoroughfares. You see a completely different aspect of a country from a river.
Every river has its own character, with perhaps the best example being the Nile where life hasn't changed for thousands of years.
Travel agents whose customers say they would never go on as cruise, should consider river cruising as an alternative.