16. A computer program product having a nontransitory computer-readable storage medium storing computer-executable code, the code comprising: an object classifier module configured to: receive information identifying a set of malicious groups associated with a social networking system, wherein a group is an entity represented in the social networking system that users can join, the malicious groups predetermined to be associated with a type of malicious activity, determine a measure of interactions of the user with the malicious group, select users associated with the malicious groups, wherein each user is selected based on the determined measure of interactions of the user with the malicious groups, and select a set of potentially malicious groups associated with the selected users; a keyword search module configured to: receive keywords associated with the type of malicious activity, and search for occurrences of the keywords in content received from users of the potentially malicious groups; the object classifier module, further configured to: determine a level of association of each potentially malicious group with the type of malicious activity based on the occurrences; and a group store configured to: store information describing the level of association of each potentially malicious group with the type of malicious activity.
16. A computer program product having a nontransitory computer-readable storage medium storing computer-executable code, the code comprising: an object classifier module configured to: receive information identifying a set of malicious groups associated with a social networking system, wherein a group is an entity represented in the social networking system that users can join, the malicious groups predetermined to be associated with a type of malicious activity, determine a measure of interactions of the user with the malicious group, select users associated with the malicious groups, wherein each user is selected based on the determined measure of interactions of the user with the malicious groups, and select a set of potentially malicious groups associated with the selected users; a keyword search module configured to: receive keywords associated with the type of malicious activity, and search for occurrences of the keywords in content received from users of the potentially malicious groups; the object classifier module, further configured to: determine a level of association of each potentially malicious group with the type of malicious activity based on the occurrences; and a group store configured to: store information describing the level of association of each potentially malicious group with the type of malicious activity. 21. The computer program product of claim 16 , the code further comprising an access control module configured to: responsive to determining that a potentially malicious group is associated with a type of malicious activity, modify privacy settings associated with the users of the group.