The comments is one way to interact with readers,they can provide in putting Criticism, Suggestions, or reports related to the article in question. It is very important of the writer to reply to every comment so that the reader feels closer to the blog he visits so that admin (author) comments can be distinguished from readers comments it's a good idea to give one marker. For example you can see it in Disqus comments, where admin comments will be give a special mark. Unfortunately the default Blogger comments have not added such a feature by default. Even though this is a trivia things, how come the blogger team hasn't added this feature even after updating the v3 layout.
How to add a blue tick on Blogger Comment
Relax you can add your own admin sign in the form of a blue tick in Blogger comments column, the method is easy you only need a few lines of CSS script.