Revain is a blockchain-based review platform. Through blockchain technology, it prevents revisions from being tampered with and deleted. The platform has a reward system for its users who write quality reviews. This is a great contribution to the cryptographic medium, because through these reviews companies can adapt their projects, thus knowing what they must change to improve. The rewards system is also quite generous, as its users can earn many RVN tokens within the platform and withdraw them to an exchange to trade for another currency. A solid project with constant updates and a very active community.