Bitcoin is in a lot of trouble at the moment.
It is not popular, since the speculators have mostly disappeared at this point. They got in on the market upswing, moving the price to almost $30 per bitcoin for a brief moment. As soon as the speculators reached their plateau, the sell-off began. Bitcoins are selling for 5-10% of what they were selling at their peak. You can expect to get between $1.50 and $3.00 per bitcoin at this point. The true believers still claim that it's coming back, but a single look at any price graph shows that in the end, anything you put into bitcoin is a lost cause. The price continues to drop as more people get out and sell what they have, plus the people "mining" bitcoins selling at whatever the current lowest price is. ALL of the major exchanges have been "hacked" at some point. I say this in quotes because there has never been any proof that the owners of each exchange didn't just decide to take the money and run, which they could have done at any time with ZERO repercussions. One of the larger exchanges was blatant enough to take everything but offer 49% back of what you lost if you'd just use them again (but accept the service fees), as opposed to the others that just delete the website and sell the coins on other markets.
The reason that this is all possible is: bitcoin isn't a currency! It is the same as trading rocks with numbers painted on them to say how much they are worth; this means there is no regulation. It's not anywhere near any other currency in the world because it doesn't have a government backing up it's value. As much as the different sites claim that it is going to change the world, bitcoin itself is being challenged in court and both results are bad for it. If it is declared a currency, the regulations alone will destroy it. If it is declared not a currency (which it is not), it will be destroyed by all sorts of fraud charges.
Stay away from bitcoin at all costs.