Sharing is called 分享 on the Taiwanese Facebook (and in my dictionary). I think I've only seen 共 in compounds for things that are already shared, communal or co

Sharing is called 分享 on the Taiwanese Facebook (and in my dictionary). I think I've only seen 共 in compounds for things that are already shared, communal or co-existant, and notably as an abbreviation for communism. 中共 = 中國共產黨 = Chinese communist party. Not really a positive connotation. :) (Disclaimer: Not a native speaker)