An Initial Coin Offering (ICO) is like a crowdfunding campaign for cryptocurrency projects. Startups issue new digital tokens and sell them to early investors in exchange for established cryptocurrencies like Bitcoin or Ethereum. These tokens might grant holders access to a future product or service, represent a stake in the company, or have other utilities. ICOs became popular as a way for blockchain projects to raise capital, but they have also been associated with scams and regulatory scrutiny due to their often unregulated nature.