Earning money by clicking on ads is generally a legitimate way to make money online.

if you own a website or blog, you can earn money through advertising by placing ads on your site. Here are some ways to do it:

1. Google AdSense: Google AdSense is a popular advertising program that allows website owners to display ads on their site. You earn money when visitors click on the ads. AdSense uses an auction system to determine which ads to display on your site, and you receive a percentage of the ad revenue.

2. Affiliate marketing: You can promote affiliate products on your website and earn a commission on any sales made through your unique affiliate link. You can join affiliate programs such as Amazon Associates or ShareASale.

3. Direct ad sales: You can sell ad space directly to advertisers on your website. This can be a more profitable option than using an ad network, but it requires you to find and negotiate with advertisers yourself.

It's important to note that earning money through advertising requires a significant amount of traffic to your website. You'll need to create quality content, optimize your site for search engines, and promote your site to attract visitors.