A few projects have done this (although more recently with EOS and Ethereum). The only notable one I can remember off the top of my head is [Clamcoin][1]:

 > Every person who had Bitcoin at block 300,377, Litecoin at block 565,693, or Dogecoin at block 218,556 was given ~4.6 CLAM.  

This has spawned a few digging services over the years, where you can upload old LTC, BTC, or Doge wallets (after removing those coins, of course) and get Clamcoin out.

On Ethereum, [0x31a240648e2baf4f9f17225987f6f53fceb1699a][2] distributed 0.000000007777777777 ETH to some 174,655 addresses as a marketing gimmick for an ICO called Safe. Many other Ethereum ICOs conduct air drops, usually with some rules like "Any address that sent or received ETH between X and Y blocks".

More recently, some EOS projects have been "spamming" [free 0.0001 EOS][3] to various accounts


I do believe that Clamcoin is the only major example of distribution based on community participation at that scale, though.

  [1]: https://bitcointalk.org/index.php?topic=623147.0
  [2]: https://etherscan.io/address/0x31a240648e2baf4f9f17225987f6f53fceb1699a#internaltx
  [3]: https://old.reddit.com/r/eos/comments/92bk3y/is_spam_advertising_through_00001_eos_transfers/