Could you list the 20 largest corporations using bitcoins.
One of the big platforms that accept BTC that I use regularly is Steam. Steam is awesome, you can buy any game you want right now with BTC and it's really fast. It's the service i've used the most times o buy things with BTC because it's more convenient than having to get your credit card, open your bank account, check balances etc.
Microsoft was also accepting BTC as far as I remember. But I have never bought anything outside Steam with BTC.
