Since, outside of science fiction, a person can only be in one place at one time, researchers should actually be focusing more on where events occurred than the particular form of the names of the ancestors involved. This is not to say that names should be disregarded, it is just more important to associate and individual with a particular location than it is a particular name.
That said, there is a rather extensive and persistent area of genealogical research known as "one name studies." One example is the Guild of One-Name Studies. This organization has the goal of research into the genealogy and history of all persons with the same surname and its variants. Here is a brief quote from the Guild's website that talks about their goal:
This is distinct from family history, in that it is the surname that is of interest, rather than the family tree of members of the same family with several different surnames. However, it does involve many of the same research skills and techniques as family history, and most one-namers are actively researching both their own family and their one-name study.In a sense, this approach is similar to what has been done by many genealogists in the past and is still being done presently. When a researcher encounters a situation where the records are sparse, particularly in a small area such as a location in Europe or elsewhere, they sometimes focus on the surname and simply "extract" all of the people in the location with the same surname. This is sort of a shotgun approach to genealogy. The supposition is that by extracting all of the people of the same name, the researcher will inevitably have located the ancestor. When I have encountered this type of research, I usually find that when the decision has been made to extract names, the research quits trying to differentiate the people with the same or similar surname into family groups and considers each as a separate individual.
My earliest encounter with this type of research was when I was reviewing and recording a great deal of genealogical research records obtained from one of my Great-grandmothers. She had a tendency to research a particular line, but if she could not find specific records about the individuals, she would just copy out anyone in a particular parish or other area with the same surname. This activity of name-gathering was very confusing for me for a considerable period of time since I could not figure out how these people in her files were related. The simple answer was that they were not related through blood lines.
As I did more research on my own surname line, I found that the genealogy was pretty simple. The line went back to an early Rhode Island immigrant named William Tanner and stopped. Despite claims by some, no has yet demonstrated with documentation, a connection to England where this particular ancestor probably originated. As I continued doing genealogical research over the years, I encountered a lot of different "Tanner families" who were not related. One time, in the Hancock County Historical Society in Carthage, Illinois, I found a card catalog with the listing of a perhaps hundreds of Tanners, all who came from Switzerland. These and many other experiences have led me to the conclusion that searching for surnames is really somewhat antithetical to the pursuit of ancestry i.e. genealogy. They are two completely different goals. Although, there is some argument for the extraction method, if the researcher is willing to spend the time differentiating each of the individuals with the common surname and separating them into family units and then further identifying the unit that is the ancestral family of the researcher.
I have absolutely nothing against people who wish to pursue one-name studies. I have found, however, that the more the name, the less help the one-name study is in assisting genealogists and, of course, I identify myself as a genealogist.
One of the most common mistakes made by people interested in genealogy, but without any background or experience, is that people with the same name are related. I get this when people ask about a relationship by saying, "are you related to Bob Tanner in Nephi, Utah" or something like that. Because of my extensive family in the western part of the United States, this question usually elicits the same answer; if that person is a member of The Church of Jesus Christ of Latter-day Saints, then the answer is probably yes. More knowledgeable individuals, who are somewhat aware of genealogy, usually ask the question differently, they say "what Tanner family are you from?"
I even have one uncle who married late in life and all of his wife's adult children who had the surname of his wife's first husband, for a lot of reasons, decided to become "Tanners" and changed their names. The more you become familiar with the limitations of focusing more on names than on places and other factors, the more you are likely to be successful in pursuing your own ancestry. But that is another topic for another time.