1. A system comprising: at least one processor for executing: a receiving module to receive, over a network at a social shopping platform, a request from a user in a first community of users, the social shopping platform includes a plurality of network-based marketplaces respectively associated with a plurality of communities, plurality of communities includes the first community of users that is associated with a first network-based marketplace; a processing application to identify the first network-based marketplace from the plurality of network-based marketplaces based on the request, the request for an activity associated with a listing that describes an item for sale in the first network-based marketplace that is used by the first community of users to transact listings of items of a single domain that is of interest to the first community of users; and a reputation module to update a listing reputation score for the listing based on a user reputation score for the user and based upon the activity associated with the listing, the reputation module further to update the user reputation score based on the listing reputation score.