Refereum is developing a blockchain-based affiliate referral ecosystem that is focused on gaming. Their goal is to develop a decentralized affiliate marketing platform that will be powered by the Ethereum-based RFR token, and will enable on-chain attribution for marketing engagements. Refereum places an emphasis on gaming, and their platform allows game developers to create incentivized quests that reward game players for completing in-game tasks.

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.

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.