1. A method for identifying a set of influential persons in a social network, comprising: using a general-purpose computing device to perform the following: ranking a list of users in the social network based on a number of friends they have on the social network; selecting as a first-ranked user a user having a largest number of friends: designating the first-ranked user as an influencer to include in the set of influential persons before deleting any users from the list of users in the social network; deleting the first-ranked user and friends of the first-ranked user from the list of users in the social network; determining that a ranked user has been deleted because that ranked user is a friend of the first-ranked user; designating a next remaining highest ranked user as the next first-ranked user; designating the next first-ranked user as an influencer to include in the set of influential persons before deleting any users from the list of users in the social network; and repeating the above process for subsequent-ranked users to generate the set of influential persons.