For decades, marketers have sought the Holy Grail of
brand loyalty. Just as the legendary grail of Arthurian
quest held the promise of extended life and renewal,
marketers attribute to brand loyalty and its sister icon, customer
retention, the promise of long-term profitability and
market share (Bhattacharya, Rao, and Glynn 1995; Reicheld
and Sasser 1990). Unfortunately, marketing’s knights-errant
face a daunting problem: They have not fully understood
what the grail looks like or where it can be found. As a
result, marketers have devised strategies and designed programs
to build loyalty with limited information about their
real impact or ultimate consequences (Dowling and Uncles
1997; Fournier, Dobscha, and Mick 1998).