You have what you think is a cool idea, but you aren't sure if you can convince investors about the sales potential of, say, a tiny monitor strapped to your face, or a watch that is also a computer. Besides, who are "investors" and how do you summon them from their secret off-shore lairs to pass judgment on your notional widget? Wouldn't it be easier if you could just put your idea on the internet, letting regular people who might be on your wavelength pledge directly to help get it done?
That's what crowdfunding is about. Services like Kickstarter, Indiegogo, Patreon and others gather funds directly from buyers, to make potentially crazy ideas a reality. Crazy ideas like a salad... made with potatoes. But it's not all free money and rampant innovation.