CiviCRM Member Sync keeps a WordPress user in sync with a CiviCRM membership by granting either a role or capabilities to a WordPress user who has that membership.
This enables you to have, among other things, members-only content on your website that is only accessible to current members as defined by the membership types and status rules that you set up in CiviCRM.
This plugin builds on the work done by Tadpole Collective and originally developed by Jag Kandasamy. Kudos.