Alternative currencies that only have value within their community can persist, but are completely reliant on their communities. Currencies that can be exchanged for other currencies have their value validated, and encourage engagement with broader communities. CoinBase legitimizes Bitcoin by providing an exchange where Bitcoin can be exchanged for US dollars. Finally, an easy way to enter and exit the Bitcoin realm.
“Coinbase Opens First Licensed Bitcoin Exchange In US” – Wired
Pretending Not To Panic 