Facebook was first introduced to add their commenting platform on blog but recently Google has introduce commenting their own commenting system to improve blogging experience. Any blog author can easily activate this commenting feature easily but you have to be bit tricky to install it on custom blogger templates. If you want to use Google+ Comment then your comments will be shared on you blog as well as on Google+ circle. And blog owner can easily get the info about the top commentators. And those who don't like blogger default comment box they would love to use Google Plus Comment widget to beautify their blog as well as you can resist spam on comment box.
How to Enable Google Commenting System on Default Blogger Templates
Step 1 Log in to your blogger account and Click on Google+ ->
Step 2 Now click on Check Box where written "Use Google+ Comments on this blog"
and now it will be automatically activate the Google+ Commenting system.
How to Enable Google Commenting System on Custom Blogger Templates
Step 1 Log in to your blogger account and Click on Template ->
Step 2 Now click on Edit HTML-> Unfold code
Step 3 Now find <b:includable id='comment-form' var='post'> by Pressing Ctrl + F
Step 4 And Paste the below code after/below <b:includable id='comment-form' var='post'> and save your template
<div class='cmt_iframe_holder' expr:data-href='data:post.canonicalUrl' expr:data-viewtype='data:post.viewType'/>
Hope this trick will improve your Google Plus commenting experience and increase your Google Plus followers rapidly. If you feel any problem just feel free to write me.