KryptoSign
www.kryptosign.io
What Jamie wrote
Very handy utility to have people digitally sign something with their Ethereum wallet.
KryptoSign solves this problem. It's a user friendly way to let users create simple documents that others can sign with their MetaMask or other crypto wallet. KryptoSign is perfect for simple contracts, guest books etc.
Can easily use for variety of things, but notably a very easy way to collect wallet addresses of people.