Facebook Inc. Chief Executive Officer Mark Zuckerberg gave cryptocurrency enthusiasts a little optimism for the new year. Zuckerberg referenced cryptocurrencies in a posting Thursday in which he laid out how he will spend 2018 trying to correct persistent problems -\u2014 including the proliferation of hate speech and misinformation -\u2014 that have dogged his wildly popular social network for the past two years. \u201cThere are important counter-trends to this - encryption and cryptocurrency - that take power from centralized systems and put it back into people\u2019s hands,\u201d Zuckerberg wrote. \u201cBut they come with the risk of being harder to control. I\u2019m interested to go deeper and study the positive and negative aspects of these technologies, and how best to use them in our services.\u201d Zuckerberg isn\u2019t the only Facebook executive expressing interest in the space. David Marcus, the company\u2019s vice president of messaging products, joined the board of Coinbase Inc., one of the largest crypto exchanges, late last year. \u201cI\u2019ve been involved with, and fascinated by cryptocurrencies since 2012, and I\u2019ve witnessed how Coinbase has started democratizing access to this new asset class,\u201d Marcus said on Coinbase\u2019s blog Dec. 12. What all this may mean for the digital currency world remains to be seen.