ARK Ecosystem is a software development company focused on Open Source & Blockchain solutions. We are the creators of the ARK Blockchain Platform (ARK.io), but we are also the creators of MarketSquare. So in that sense, MarketSquare is an ARK product.
From the perspective of MarketSquare, it is a more platform agnostic product focused on the industry as a whole and trying to provide a better system for discovery and community building for all of the great projects out there. That includes ARK, Hive, and many others.