When developing YaSM we also looked into COBIT (Control Objectives for Information and Related Technologies, a framework maintained and owned by ISACA). We wanted to ensure that YaSM and COBIT can be used in combination, but YaSM cannot claim to be some kind of "COBIT process model".
With its complete set of goals and metrics for IT processes, COBIT is a popular choice with organizations that wish to improve their IT governance, but it is less helpful for designing an organization's service management processes. Although COBIT defines a process model complete with suggested process activities, its authors concede that "the activities may not be at a sufficient level of detail for implementation, and further guidance may need to be obtained from specific relevant standards and good practice such as ITIL, ...".
This is where YaSM comes into the picture. YaSM and ITIL are well aligned but YaSM is somewhat easier to implement, so using YaSM and COBIT in combination is quite conceivable when setting up a set of service management processes, including a suitable governance framework.
In the YaSM Wiki we provide a detailed account of the COBIT enabling processes and how they relate to specific YaSM processes, to illustrate that YaSM and COBIT share many basic principles.