These are more about interaction than action: players either join their friends for an online game of poker or Scrabble, or to create and show off virtual pets, farms and mob families.
Whether confessing that important piece of information to either my colleagues urging me to join in a game of high-stakes poker or to my father in a best-of-three pool match down the pub, I can honestly say that I have saved both a fair amount of embarrassment and incalculable amounts of money by putting my cards on the table at the outset.