The Like button is a way for people to show their appreciation for your posts. It’s also a way for authors to show the world how popular their content has become.
You can turn Likes on with these two steps:
Since Likes is a feature we brought to Jetpack from WordPress.com, your readers will need to be logged in to their WordPress.com account to be able to Like one of your posts.
By default, the likes feature is disabled for Jetpack. Once enabled, the Like button will be displayed under each post. It will display a gallery of Gravatars of each user that has liked your posts.
You can enable the module from the Jetpack activation screen and then configure where it should show using the “configure” button. The likes area uses the same settings as the “sharing” module to show the buttons.
If you’d rather, you can turn off the like button for specific posts. When editing a post, find the Likes and Shares module (you might have to scroll down to find it). It will contain an option labeled Show likes on this post.
You can toggle this on or off, just like controlling comments and trackbacks. When you’ve set it, either publish or update your post to save the change.