The number of Facebook users has exceeded 1 billion. It is just what you are looking for. Easy to install and set up - it takes only 5 minutes to set it up and run!
Facebook Like Button Plugin allows you to add a Follow button the easiest way. Fully configurable and customizable to your likings. Configure the button position: before the content, after, before and after or using a shortcode.
Looks great and easy to use. That is everything you need.