Bitcoin is the main digital currency that everyone is talking about right now. But, as investors close in on the 21 million coins that exist, other currencies are gaining in popularity. Whether this is a good thing or a bad thing is still unknown. But, when you think about it, any type of money is risky - not just digital currency.
There are some issues with hacking where people have lost their bitcoins. Additionally, there have been issues of fraud where someone misrepresented themselves and were really sending you to a fraudulent website to pay money for non-existent bitcoins.