Investing.com - In the dynamic, world of cryptocurrencies, it's often a case of one step forward, one step back. And it's happening on a weekly, if not daily basis, as these recent example show,On the positive side, a ratings agency issued grades on cryptocurrencies for the first time.Weiss Ratings issued ratings on 74 currencies, giving Ethereum a "good" B rating and Bitcoin a "fair" C+ rating.Then stock trading app Robinhood said customers in five states will be able to trade Ethereum and Bitcoin through its app starting in February. The free app popular with Millennials plans to offer trading in more coins in the future.On the negative side, South Korea put an end to anonymous cryptocurrency trading accounts. Investors won't be able to trade cryptocurrencies unless the name on the crypto exchange matches the one on their bank account.At the same time, two U.S. regulators said they are paying closer attention to cryptocurrencies. The heads of the Securities Exchange Commission and the Commodities Futures Trading Commission said in a Wall Street Journal article that they are devoting a significant part of their resources monitoring digital currencies in an effort to stamp out fraud.