2. The method of claim 1 , wherein the candidate score associated with each candidate group is further determined based in part on one or more affinities between the target user and users in a candidate group.
2. The method of claim 1 , wherein the candidate score associated with each candidate group is further determined based in part on one or more affinities between the target user and users in a candidate group. 3. The method of claim 2 , wherein determining the candidate score for each candidate group comprises: determining affinities between users in the candidate group and the target user; determining a level of activity of users in the candidate group; for each user in the candidate group, determining a product of an affinity between a user in the candidate group and the target user and a level of activity of the user; and summing the products.