15. A computer-implemented method comprising: obtaining keywords from user profiles of a group of users of a social networking system who previously responded to an invitation; extracting a set of keywords from a subject user profile of a subject user of a social networking system; comparing the set of keywords to the keywords from the user profiles of the group of users of the social networking system who previously responded to the invitation; and predicting a response to the invitation by the subject user based on the comparison.
15. A computer-implemented method comprising: obtaining keywords from user profiles of a group of users of a social networking system who previously responded to an invitation; extracting a set of keywords from a subject user profile of a subject user of a social networking system; comparing the set of keywords to the keywords from the user profiles of the group of users of the social networking system who previously responded to the invitation; and predicting a response to the invitation by the subject user based on the comparison. 24. The method of claim 15 , wherein the set of keywords includes words relating to usage.