I wonder how this is achieved as I am unable to have formatting options in comments that I make, which makes the comment bit unreadable. I would be surprised if it just because of lack of in sufficient reputation as this should be available for any user as it only helps in better readability (if correctly applied ).
If you click the "help" link next to a comment box, you'll get a popup with the following information:
Comments use mini-Markdown formatting:
[link](http://example.com) _italic_ **bold**`
code`. The post author will always be notified of your comment. To also notify a previous commenter, mention their user name:
@PeterSmithwill both work. Learn more…
If you follow the "Learn more..." link you'll get more information about formatting comments than you would think there would be.