The Collaborative International Dictionary of English v.0.48:
Sharer \Shar"er\ (sh[^a]r"[~e]r), n. One who shares; a participator; a partaker; also, a divider; a distributer. [1913 Webster]WordNet (r) 3.0 (2006):
sharer n 1: someone who has or gives or receives a part or a share [syn: partaker, sharer]