Wow, what a week this has been! Since Sunday, when our first episode on Bitcoin went live, the value of Bitcoin has come down from around USD 8000 to below USD 6000 and back up to almost past USD 8500 again. You may dismiss this as yet further proof of how unhinged cryptocurrencies are, the week has been pretty crazy for various assets, so don’t go jumping to conclusions yet—at least, not until you’ve given a listen to our follow-up episode that answers the question what you can and cannot do with Bitcoin and other cryptocurrencies. If you’re asking yourself what else could we possibly tell you about virtual currencies after our exhaustive episode last week, wait till you hear about CryptoKitties. It is a game, where users breed and trade digital cats. “CryptoKitties are … bred by spending Ether tokens on smart contracts that use two base cats to create a new one. Each resulting cat is unique and persistent,” news site The Verge reported dryly recently. Which means that unlike Tamagotchi, the cat doesn’t die if you don’t digitally feed it. It will continue to represent the investment in virtual currency that you put into it. That’s the store of value, in feline form. (Ether tokens, by the way, are cryptocurrency, too.) But with the 25% daily price fluctuations in virtual currencies, do they really store value? Markus Willms, who works on systems and data management in the European Investment Bank’s Finance directorate, proposes some explanations for the extreme volatility of Bitcoin. One is the feedback loop, in which people who sell a large amount in Bitcoins will have an outsize influence on the market, because of limited liquidity. Media coverage is also a factor (as is our podcast, surely). Markus also discusses possible regulation of these currencies, the possibility of central banks issuing virtual currencies, and virtual currencies that are actually pegged to real-world currencies. He goes on to tell us why currently Bitcoin is not well suited to actually help you buy a cup of coffee. That’s because it is more like digital gold, which you wouldn’t use at Starbucks, either. Gold, however, is a useful way to store value. And Bitcoin could be, too (if it, indeed, stored all its value for longer than one of our A Dictionary of Finance episodes). Finally, you won’t want to miss our eternal idealist Matt asking the million Bitcoin question: Is this good for the world?