If you promote affiliate products, this means that you promote someone else's products and they give you a commission for each sale. There are many rules and regulations you must follow in order to practice affiliate marketing properly. The truth is, the more transparent you are, the better.
One thing to remember is that being transparent in business is beneficial to everyone. Letting people know that your link to that helpful product is an affiliate product promotions trust. Giving the link without telling may not seem like a problem, but some people do get upset about that and feel as if they were lied to.By law you are required to:
Provide Contact Information
You can not hide behind your computer and not be who you really are in today's online world, and you should not want to. You're there to serve your audience and customers and they need to get in contact with you. Provide easy to find contact information in as many ways as you can afford.
Provide On-Page Disclosure
Every visitor that comes to your page should have the opportunity to read that you earn money via affiliate links and product promotion. That means that on any page you sell a product, you should include the disclosure. You can find a plugin to help with this, or use shortcode if you use WordPress.
A Policy Page
Create a whole page devoted to explaining all your policies so that any website visitors can look at that page to find out the nature of your business. You should address all partners, how things are fulfilled, communication, and so forth. For example, your customers should know that if they buy something from a link, they should seek customer service for that product with the place they purchased from – but that you still want to know if they have more problems.
Other Useful Data
The fact is, any data you can provide makes you more transparent. It also makes your audience's experience feel safer and makes them more comfortable. For example, include testimonials, recommendations, short reports and so forth about the products you are recommending. Anything you think will help build trust and make you more transparent to your audience you should do.
But, even if it was not a matter of law, transparency really builds that know, like, and trust factor that everyone wants so badly. When you tell people that you are making money promoting something, it does not take away from the fact that you're selling something that solves their problem.