If you held EOS on April 15th, you are getting free eosDAC ERC20 tokens transferred to your ETH address.
They are distributing eosDAC tokens now. The order of distribution is interestingly from smallest to largest holder of EOS. I think they are distributing in this order to prevent(delay) dumping of tokens from whales.
You can check the status from etherscan.io:
And don't forget to register your Ethereum address if you are holding EOS in your own Ethereum wallet before June 1st. If you hold it in an exchange, check if they are swapping the EOS ERC20 tokens to the EOS mainnet. If you hold it in Metamask, it's easy to register your EOS tokens. Exodus wallet also supports registering your EOS tokens. If you hold it in a different wallet like MyEtherWallet, you will need to do some googling. Don't forget to register your EOS tokens.
I'm holding EOS in my Metamask wallet, and you should safely store your EOS public and private keys.