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 0.06
TRX 0.30
JST 0.059
BTC 70555.89
ETH 2139.57
USDT 1.00
SBD 0.51