ICO stands for 'Initial Coin Offering'. It is a form of a crowdfunding campaign utilized by cryptocurrency startups to raise capital for their projects. During an ICO, investors purchase tokens or coins in the project before it is released to the public. This allows the project to secure funds early on and incentivizes investors to contribute by offering them the potential for financial gain if the project is successful. The tokens or coins can be traded on cryptocurrency exchanges or used as currency within the project's ecosystem. It is important to note that ICOs are largely unregulated and investors should carefully evaluate the project before investing.