Sentence:  The <WSD>rainmakers</WSD> realize that the cost of obtaining a new client is much higher than that of keeping an old one. Many affirm that their relationships mean something to them beyond the possibility of future work. Whatever the reason, they never lose touch. These core elements are what make <WSD>rainmakers</WSD> different from other people. 
Meaning of the word marked with <WSD> tags:  A person having the ability to generate business, raise funds, or otherwise engineer success for a company, organization, etc.