Have you ever encountered free party or meetup and realised that half the people registered did not actually turn up? BlockParty solves this problem by providing a simple incentive for people to register only if they mean it.
BlockParty is not Proof of Concept nor vaporware. It was first used at DevCon2 in Shanghai depositting real Ether, then have been used to manage local Ethereum meetups and social events.
Most meetup sites look as if there are lots of participants but half of the participants won't be there. On the other hand, Blockparty incentiveses people to only sign up when they mean to, leading to the great transparency