I’m sometimes asked what the difference is between genealogy and family history. These terms are used as if they’re interchangeable but strictly speaking genealogy refers to the tracing of particular lines of descent. Family history indicates a wider focus of research: uncovering the details of the ancestors’ lives and times. The phrase ‘putting flesh on the bones’ is overworked; nevertheless it’s what the family historian is attempting to achieve. Theoretically it might be possible to be a genealogist without being a family historian – but not vice versa.
Returning to the subject of surname distribution and frequency, the name Swires – my paternal grandmother’s maiden name – is far from commonly-found: only three instances per million people in the UK, the current total number with that surname being 130. At the time of the 1881 Census there were 106 individuals named Swires in Yorkshire, pointing to a concentration of the surname in my grandmother’s family’s county of origin. In comparison with this rarity of occurrence, Gadsden - my father's surname - crops up 12 times per million people in the UK, and is most numerous in Bedfordshire and Buckinghamshire. Gadsdens are very thin on the ground in South Africa, but there are thousands in the US. Variant spellings of Gadsden cause complications: GADSEN, GADSON, GADESDEN etc.
For a specialist’s view of the topic and some remarkable nuggets of information, I recommend Colin D. Rogers’ book, The surname detective: Investigating surname distribution England, 1086-present day.