Bitcoin has gathered a lot of value, however, very little of this value comes from economic activity (GDP) which is what would traditionally give a currency its value and stability.  Bitcoin is actually designed like a commodity (creation of Bitcoins was modeled after mining gold), and like other commodities, much of the value is derived from speculation of that commodity (not from its acceptance and usage to buy and sell goods).  Some major companies are announcing acceptance of Bitcoin, but at the moment, that likely drives more media attention than sales via Bitcoin.  Given the high ratio of accounts speculating to those actually transacting, the value of Bitcoin will continue to be quite volatile, rising and falling with speculation and could collapse quickly to a rather low value.  If more Bitcoin account holders use Bitcoins to buy and sell goods rather than to stockpile Bitcoins in a speculative fashion, then the value of a Bitcoin will become more stable.