Plug is liking for money. Plug is a web site promotional tool that generates more relevant traffic and, therefore, more sales for on-line merchants. Plug allows people to like products, or web sites, and automatically promote them through social media which gives leverage, i.e. a merchant’s products are then seen by more people that are likely to share the same demographics as the person who liked the product. Using Plug is effectively free for those merchants that use an affiliate marketing company. Plug is a tried and tested concept that works.