The 21 app allows you to earn bitcoin in exchange for answering messages and completing tasks. Users set up a 21.co public profile, enabling others to send messages and tasks to the user without revealing personal contact information. After answering a message or completing a task, you will receive a task reward in bitcoin.
Cryptocurrency spam solution. BitBounce reduces your email spam by charging unsolicited email senders a cryptocurrency fee to send you their emails.
When senders pay your cryptocurrency fee, their emails are moved to your inbox.