check the comments on this page. Is this author seriously replying to spam?
 

http://www.trendyupdates.com/free-ar...-with-high-pr/

the author is seriously answering all generic spam comments one by one, wtf :1orglaugh

This guy has to know it's spam or he's completely oblivious. Maybe it is his way to make the best out of spam messages, to just write reactions to them so it seems for google that there is interaction or something? Because nobody can be this oblivious.

All the comments are nofollow so it doesn't affect him. Maybe Google looks at the number of comments as being interaction?
I used to do something similar but edit comments so they made more sense.

Maybe he did it so people would post it on forums to laugh at him and in the process, drive traffic to his site.