One of the best ways to promote products or links are the ones you have mentioned, Social Media and Forum. Why? Because social media specifically Facebook have millions of users. The larger number of users, the more chances that your products will be promoted. I think you just need to know what is the most effective way of using these platforms. Most of the influencers uses social media in promoting the products. Social media is also effective to promote the website where the complete line of products was published. On forums, most users went there for reviews and rating of a certain product.  And this method is also a great way to promote our products.