Counterparty is a platform for user-created assets on Bitcoin. It’s a protocol, set of specifications, and an API. Taken together, it allows users to create and trade assets on top of Bitcoin’s blockchain. In this way, Counterparty is similar to platforms like Waves or Ethereum. Of course, the difference is Counterparty integrates directly with Bitcoin. Therefore, it comes will all the security and reliability (and issues) that are part of the Bitcoin blockchain. This is a fairly old project. In fact, it pre-dates Ethereum with its launch in 2014. It was the original asset creation mechanism. As you’re probably aware, Counterparty has faded from prominence over the years. This is largely due to the rise of the ERC-20 token standard on Ethereum.
While we’ve become used to calling blockchain assets, tokens, it doesn’t necessarily have to be the case. An asset can represent anything that has value or is rare. As a result, Counterparty steers clear of the word “token” in their marketing and documentation. They’re much more interested in digital assets of all kinds, not just currencies, securities, and utility tokens. Digital assets can be a digital marker of a physical object, an easy way to manage shares in your company, or reputation karma for a website. These are all types of assets you could create on Counterparty (or Ethereum or Waves, for that matter). Counterparty creates the set of rules, requirements, integrations, etc that are necessary for assets on the Bitcoin blockchain. It’s the infrastructure behind user-created assets in much the same way that the ERC-20 protocol sets up guidelines and standards for asset creation on Ethereum.