2Key network is a blockchain based platform for building referral campaigns. 2Key allows users to create and manage online campaigns that are powered by smart contracts. The Ethereum based 2KEY token is used to activate campaigns and to reward users for their participation.

AdCoin is an ad network for cryptocurrencies. It was created to allow cryptocurrency related products to be advertised more transparently, with digital ad campaigns that will reach their target demographic. The company is developing plugins, API's and other tools that can be used to connect publishers and advertisers, in a crypto-powered ad exchange.
There are no minimum budgets for campaigns. The network that is fueled with the ACC coin, which has a Proof-of-Work (PoW) consensus protocol.

AdEx is a decentralized advertising exchange built on the Ethereum blockchain. They hope to use blockchain to improve privacy, transparency, and security for viewers, publishers, and advertisers. The network is powered by the ADX token.