Re: facebook, Instagram, Whatsapp Are Down - But Bitcoin is as strong as ever !!!
when such gaints can run into a problem, what makes you think they can't be shut down ?
LONG LIVE BTC,100% UPTIME 
The Bitcoin network has been functional for 99.99999 % not 100%. There was a bug that was fix-it by satoshi. But most people consider this event as a downtime.LONG LIVE BTC,
block 74638 August 15th
Some people consider the "Accidental Hardfork" downtime too.