According to Wikipedia.org

A permalink is a URL that points to a specific blogging entry even after the entry has passed from the front page into the blog archives.Permanence in links is desirable when content items are likely to be linked to, from, or cited by, a source outside the originating organization.An entry in a blog with many entries is accessible from the site’s front page for only a short time. Visitors who store the URL for a particular entry often find upon their return that the desired content has been replaced by something new. Prominently posting permalinks is a method employed by bloggers to encourage visitors to store a more long-lived URL (the permalink) for reference.

The New Blogger platform already provides a Permalink feature

A permalink is stored as a link under the post in the form of time stamp.For example 11:38 AM in the above picture.When the mouse is hovered over the time stamp the permanent link is seen in the staus bar of the explorer.

Many of us didn’t know that & it usually get unnoticed.Also it can be disabled under the Blog Posts Option in the Page Layout under the Template Menu.

So here is the quick trick to add a Permalink under the post, as you are seeing in this blog.

First make a backup of your blogger template.
Open your blog template & click on Edit HTML with Expand Widget Templates checked.Here we are going to add a Permalink option after the Comments link(as seen in the picture above).
In the HTML Code just search for these lines

Just after these lines add the following line of code

You are done.Just save your template.