Basically Initial Coin Offering or ICO rom what I undertand is a way of a project to crowdfund their project by offering tokens or coin to early investors before it wven hits the market. In that way, ICO participants will have the advantage to get more tokens with discounts compared to what will the price of the coin in the market once it's realeased. they use the money they gather on ICO for further development of the project and sometimes for marketing as well.