6. The method of claim 1 , wherein the edges of the social network graph are weighted differently for at least two of: T-T edges that connect social network nodes representing two social network posts; T-U edges between a social network node representing a social network post and a user node representing its author; and U-U edges between nodes representing two users who are in a follows relationship.
6. The method of claim 1 , wherein the edges of the social network graph are weighted differently for at least two of: T-T edges that connect social network nodes representing two social network posts; T-U edges between a social network node representing a social network post and a user node representing its author; and U-U edges between nodes representing two users who are in a follows relationship. 8. The method of claim 6 , wherein at least one of: the T-T edges of the social network graph are weighted based on their textual content similarity; the T-U edges of the social network graph are given a maximum weight; and the U-U edges of the graph are given an intermediate weight which is less than for the T-U edges.