Initial Coin Offering (ICO) is almost similar to crowdfunding...I think the big difference is that when we are talking about ICO we mostly linked it to projects in the cryptocurrency sphere while crowdfunding can be any project that is looking for source of capital usually coming from small investors. There had been many crowdfunding platforms that became famous like IndieGoGo...I think those are actually predecessor of the ICO platform (though some may not agree with me on this comparison).