Crowdfunding is a method of raising funds from a large number of people, typically via online platforms. It began in the early 2000s, gaining popularity with the rise of the internet. There are four main models:
1) Donation-based, where contributors give without expecting returns
2) Reward-based, offering perks or products in return
3) Equity-based, where backers receive shares in a business
4) Lending-based, involving repayment of funds with interest.