There are many different (unrelated) families of this surname, arising independently and through "non-paternal events" (illegitimacy, adoption, and name change). Y-DNA testing of males with this surname can determine which families of this surname share a common direct paternal ancestor with you (and which do not). This enables you to find common lines of descent that can be researched with others, and where to best focus your research efforts. Key to this is getting representative males (with this surname) of each branch of your family tested (to at least 37 markers) and provide information about your earliest known direct paternal ancestor and your linkage to him to this project administrator.