David Marcus, a VP at Facebook since 2014 is stepping down from the board of directors at cryptocurrency exchange Coinbase, citing his new assignment at Facebook leading the social media giant's blockchain strategy. Marcus was named Facebook's new blockchain research lead recently. The company has not released any details about the work it is doing in the field, though Marcus' team reportedly has fewer than a dozen members. A Coinbase spokesperson said Marcus' decision to step down was made to avoid the appearance of a conflict of interest, but declined to elaborate.