1. A method, comprising: accessing logical relationship information describing logical relationships among a plurality of users; pushing tuning parameters to a first user device operated by a first user, the tuning parameters specifying weights and/or functions to be applied to data previously generated by one or more sensors on the first user device, the one or more sensors indicating various environmental conditions in the vicinity of the first user device; receiving tuned data from the first user device, the tuned data representing data from the one or more sensors that has been tuned in accordance with the tuning parameters; determining, using at least one processor, potential membership of the first user in a first group of users based on the logical relationship information and the tuned data, by selecting the first group from a plurality of possible groups, the selecting being based on scores generated, for each of the plurality of possible groups, by a candidate scorer module using the tuned data, the first group of users containing a plurality of users, including one or more users who are not logically connected to the first user; and adding the first user to the first group of users based on the determination.