HTMLCOIN is a Proof-of-Stake (PoS) blockchain platform focused on enabling the practical applications of smart contracts. The HTML blokchain is a hybrid of Ethereum and Bitcoin, and also combines elements of other blockchain infrastructures.

Primecoin is a cryptocurrency based on finding prime numbers. Identifying prime numbers plays a central role in cryptography. Primecoin's unique Proof-of-Work (PoW) consensus mechanism is able to increase transaction speeds and improve energy efficiency.
The network searches for special prime number chains known as Cunningham chains and bi-twin chains, which are of interest in mathematical research.

PLATINCOIN is a Proof-of-Stake coin that is minted instead of mined. Users participate in managing the network by renting hardware space from the project organizers for a period of 36 months. These computing resources will drive the PoS consensus, and the users that rent the hardware will be rewarded with newly minted PLC coins.