ICO stands for Initial Coin Offering. It is a fundraising method used by cryptocurrency startups and projects to raise capital by issuing and selling their own tokens or coins to investors. ICOs gained popularity during the cryptocurrency boom in the 2010s as a means for projects to secure funding for development and operations.

During an ICO, the project team typically creates a whitepaper that outlines the details of their project, including its goals, technology, and roadmap. They then offer a certain number of their tokens to the public in exchange for established cryptocurrencies, such as Bitcoin or Ethereum, or sometimes even fiat currencies.

Investors who participate in an ICO usually do so with the expectation that the value of the project's tokens will increase over time, allowing them to make a profit. ICOs have attracted both individual retail investors and institutional investors looking to support promising blockchain projects.

However, it is important to note that ICOs have faced regulatory scrutiny and evolving legal frameworks in many jurisdictions due to concerns around fraud, scams, and investor protection. As a result, alternative fundraising methods such as security token offerings (STOs) and initial exchange offerings (IEOs) have emerged to address some of these concerns.

Overall, ICOs have played a significant role in the growth of the blockchain and cryptocurrency industry, enabling projects to secure funding and allowing investors to participate in early-stage opportunities.