"Buyers in almost any market fall into one of two groups - those who are extremely loyal to their supplier and those who systematically 'search' for good bargains."

"In particular, the most frequent buyers (those who visit the market more than once a week), with very few exceptions, visit only one seller, while less frequent buyers visit several sellers."

In a coevolutionary process, buyers learn to become loyal as sellers learn to offer higher utility to loyal buyers, while these sellers, in turn, learn to offer higher utility to loyal buyers as they happen to realize higher gross revenues from loyal buyers.