Having a Facebook Page for our blog is a great way to promote it.
Facebook Pages give you a more dynamic relationship with the public
figures and organizations you are interested in. In simple words, it
helps us to share blog updates to the interested facebook users who
become a ‘fan’ of our blog 
This post gives you a simple tutorial on how to add a Facebook Like Box widget to your blogs. If you haven’t created a facebook page yet, you can do it from here.
How to Add FaceBook Like Box to self-hosted WordPress:
You can do this simply by installing Facebook Like Box Widget to your wordpress. It allows you to enable Facebook Page Like Box through a widget. Refer the Installation and Screenshots sections for more help.How to Add FaceBook Like Box to Blogger (blogspot):
- Go to FaceBook Plugins page HERE.
- Fill your Facebook Page URL or ID and customize the widget properties according to your requirements.
- After customizing the widget, click Get Code. Then copy the iframe widget code.
- Go to Blogger Dashboard – Layout/Design – Add a Gadget – HTML/Javascript – then paste that widget iframe code and Save.