Seems to me with the giant interweb companies knowing everything about everyone this would be an area they would excel at.

Group the people who are similar enough, so there won't be excessive drama, yet from different enough backgrounds so they can expand their horizons.

After the semester I spent in the dorms I'm glad I'm not still in prison due the one roomate (out of four) who was just incompatible with everyone else which almost lead to his defenestration on more than one occasion.