Monero, abbreviated as XMR, debuted on April 18th 2014, 3 months after Dash. The total supply is capped at 18.44 million. As of January 2018, the circulating supply stands at 15.62 million.
Monero has no fixed block size, thereby eliminating scalability risks. Monero provides anonymity by utilizing ring signatures.
What is a ring signature?
The Monero network would first mix the signatory’s public key with another public key before signing a message, making it impossible for other to find out who’s the actual signer.
This is similar to the submission of joint petitions in ancient China where the identity of the person who initiated the petition is protected by having all the signatures in the shape of a ring, without any indication of sequence, thereby hiding the identity of the initiator.
Monero even allows the address of the receiver to be hidden from the sender and the identity of the sender to be hidden from the receiver.