Sort:  

Bitcoin is an open-entry system, meaning anyone can participate, or start mining.

But having three mining pools controlling over 51% of the hashing power isn't exactly decentralized...

Coin Marketplace

STEEM 0.18
TRX 0.15
JST 0.029
BTC 63361.04
ETH 2483.47
USDT 1.00
SBD 2.67