Explain what is meant by the relationship marketing ladder

拜托 了，， 要精通英文的

我只知道relationship marketing
但是不知道什么是relationship marketing ladder 你确定没写错么

Relationship marketing is a form of marketing
developed from direct response marketing campaigns conducted in the
1970s and 1980s which emphasizes customer retention and satisfaction,
rather than a dominant focus on point-of-sale transactions.

Relationship marketing differs from other forms of marketing in that
it recognizes the long term value to the firm of keeping customers, as
opposed to direct
or "Intrusion" marketing, which focuses upon acquisition of new clients
by targeting majority demographics based upon prospective client lists.

意思说 什么是营销关系的阶梯

解释什么是关系营销的阶梯 绝对正确