Managing the relationship with customers is still a problem, as Dilbert shows today. The traditional "IT expert" is not the ideal partner for the customer.
In ITIL 2011, Business Relationship Management (BRM) now is one of the 26 "official ITIL processes". In the previous version of ITIL it was completely missing. Activities that used to be described in Service Level Management (SLM) are now part of BRM.
Example: "Business relationship management receives a request for a new service or a change to an existing service. Service portfolio management helps to define and formalize this request before submitting it to change management in the form of a change proposal."
As the ITIL authors write, "Unless the relationships between business relationship management and other service management processes are clearly identified, there is potential for confusion about the boundaries between them. " The main difference, as described in ITIL, is that BRM is concerned with customer satisfaction and SLM is concerned with agreeing and achieving service levels.