The growth of the Online Platform Economy (OPE) has been contributing to the changing nature of work. Is this marketplace building momentum towards systemic change in the labor force, or will it remain a small market for supplementary income? In previous work we highlighted that growth in participation on labor and capital platforms has peaked. As of June 2016, participation on labor platforms has doubled year-over-year, but participation on capital platforms has leveled off. In this report, we explore the dynamics of participation and earnings in order to better understand how growth has slowed. We draw from one of the largest samples of platform participants to date: over 240,000 anonymized individuals who have received platform income between October 2012 and June 2016 from one or more of 42 different platforms. Our findings point to several dimensions of how the growth in online platform participation has slowed.