Hi. It’s different for everything, but for me, if an article receives over 1k views per day, I consider it a viral article. I suppose you can classify “viral” into “baby-viral”, “semi-viral” and “viral”. Out of the 3 articles I mentioned, I would consider the 3rd one a viral post (after all, it made me over $1,000 in less than a month), and the first two as semi-viral.