[infiniteri]

Probably to help someone know what paragraph you're referencing if you're having a discussion. I could see it working better if it only appeared when you hovered over to the left of the paragraph.

[benbreen]

Yep. The main function is to situate the reader if they get linked to a "supernote" like so:

http://theappendix.net/issues/2014/7/party-like-its-1999-jap...

[kingnight]

Makes some sense. Seems excessive.

Not trying to being entirely negative... This is a really great article!

[Kurtz79]

To be fair it did catch my attention as well, it´s just uncommon.