Bitcoin has grown into a very robust network. I think it's one of the strongest there is.

In 2010 a guy known only as ArtForz secretly built a Bitcoin mining farm that controlled 25% of the entire network

The whole network was a few hundred people running it on laptops

Satoshi himself had publicly asked the community for a “gentleman’s agreement”: please don’t switch to GPU mining, it would ruin the fairness of the network

Most people respected the request

ArtForz did not

In July 2010 he wrote his own private GPU mining software and quietly turned it on

The CPU miners on the network were doing maybe 10 megahashes per second

ArtForz’s GPUs were doing hundreds. He was mining 50 to 100 times faster than every other participant

On July 25, 2010 he posted that he had mined 1,700 BTC in six days

Within a month he controlled approximately 10% of the entire Bitcoin network. By December he was at 25%

He called the operation “ArtFarm.” 24 ATI Radeon HD 5970 graphics cards stacked on shelves. The cards he didn’t mount were stored in CARDBOARD BOXES on his floor