For this questions USCIS is trying to determine what organizations (organization, association, fund, foundation, party, club, society, or similar group) you have ever been involved with. The spirit of this question is to learn more about your background, including security related aspects, as your memberships are generally a good indicator of your past.

For example: if you were a part of military, Communist Party of China (CCP) or some other organization that is similar in nature; this includes a wide variety of membership types.

You should include any memberships you have currently or have had in the past to the best of your knowledge. Omission of such information can lead to severe complications with your petition.