For start-ups and small businesses choosing a phone number is often one of the first decisions. After all, this will be used for reaching and keeping in contact with customers, employees, suppliers, etc. Much like a professional and branded domain name and email, a phone number identifies and reflects your business (read why NOT to use a mobile number).
Typically, the decision of selecting a business phone number was closely associated with the trading location of the business as landlines were, by definition, tied to a premise...but no longer is this the case.