29. A system comprising: at least one processor for executing: a receiving module to receive a request, over a network at a social shopping platform, from a first 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, the 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 to initiate an activity with a second user, in the first community of users, in the first network-based marketplace that is used by the first community of users to transact listings that describe items of a single domain that is of interest to the first community of users; and a reputation module to update a first user reputation score for the first user based on a second user reputation score for the second user and based upon the activity initiated, the reputation module further to update the second user reputation score based on the first user reputation score.
29. A system comprising: at least one processor for executing: a receiving module to receive a request, over a network at a social shopping platform, from a first 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, the 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 to initiate an activity with a second user, in the first community of users, in the first network-based marketplace that is used by the first community of users to transact listings that describe items of a single domain that is of interest to the first community of users; and a reputation module to update a first user reputation score for the first user based on a second user reputation score for the second user and based upon the activity initiated, the reputation module further to update the second user reputation score based on the first user reputation score. 31. The system of claim 29 , wherein the first user reputation score is based on the second user reputation score being scaled by a value that corresponds to the activity.