BuddyPress, part of the WordPress eco-system.
More on BuddyPress.
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Possible users of BuddyPress:
– BetFair – TradeFair
– InTrade – TradeSports
– HedgeStreet
– Betdaq
– Hollywood Stock Exchange – Cantor Exchange
– HubDub
– NewsFutures
– Inkling Markets
– etc.
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