Bitcoin is an anonymous form of currency, that allows people to, you guessed it, anonymously purchase things on the deep web. Most of the time, these include narcotics, guns, and other illegal things. You could, in a sense, say that Bitcoin is the currency of the deep web. it's untraceable(despite what b class tv shows may say) And allows for an anonymous transfer of money, what you choose to do with it, is up to you. I highly suggest NOT going onto the deep web unless you are experienced, and know what you are doing. It is a very dangerous place, with very real cyber threats.