What are stablecoins, and how do they differ from other cryptocurrencies?

The price of bitcoin, ether and other popular cryptocurrencies plunged this week as investors trimmed their losses and sought refuge in less volatile assets. One catalyst for this week's rout are growing concerns about so-called stablecoins, another kind of cryptocurrency that is supposed to protect buyers from the sharp swings typical of virtual money. 

Read on to learn about stablecoins.