CPA Protocol is designed to enhance active user engagement for other protocols through CPA (Cost per Action) campaigns. By integrating with the Graph, it offers flexibility in defining an active user's criteria, such as token swaps or liquidity provisions, based on specific sub-graph actions. Influencers can promote these campaigns, and in return, CPA Protocol issues them a "Collab NFT" via the Zora NFT Factory. Influencers then encourage their followers to mint this NFT and fulfill the campaign's criteria. (To be noted, to ensure genuine user participation and prevent Sybil attacks, we've incorporated Worldcoin ID to verify the authenticity of users during the NFT minting process.) Once achieved, rewards are directly distributed to the influencers, ensuring a direct market expense to active user conversion. The most important impact is that, by adopting CPA Protocol, not only the protocols can easily boost the user engagement of their product, but by including the influencer in the reward system, they could also build up a community effortlessly. Decoupling the pain and efforts of marketing and building community from the core team, the core team of the protocols could focus more on their product.