1. A method comprising: processing a first text created by a user using an online service into a first bag of words, the first bag of words comprising a list of words that appear in the first text, each of the words having associated therewith a number representing a number of times the associated word appears in the text; computing a similarity between the first bag of words and at least one second bag of words, wherein the computing comprises, for each word in the first bag of words, determining a compare count comprising a minimum number of times the word appears in each of the first bag of words and the second bag of words and adding the compare count to a sum of counts, wherein the computed similarity comprises two times the sum of counts divided by the total number of words in the first bag of words and the second bag of words; comparing the computed similarity with a threshold; and determining that the user is a spammer and preventing the user from using the online service to create additional texts if the computed similarity is greater than the threshold, wherein the first text comprises a user profile of the user in connection with the online service.