I think it should describe what information you collect from your visitors and more importantly, what you do, or don't do with it.
Many affiliate programs require a site to have a privacy policy before they will partner with you.
IMO, any site that hopes to have visitors, should have a privacy statement.
IMO, any site that offers a product or service for sale or trade, should have a terms and conditions statement, that the user agrees to, before the purchase.
The policies, both Privacy and Terms, can be long and convoluted which IMO causes the visitor NOT to read them. Or, they can be short and concise.
Here is my PP at
Freelance411