Maybe it needs further explanation? Ink being the object with which books are created, and knowledge put down for others to use, you must be careful to avoid using that object directly and believing you have gained knowledge from it.

The blog post itself isn't the great insight, nor is the Reddit software it's running on, or the comment system, or the upvoting and downvoting. Insight can only come from the mind, and understanding the words and how they all link together into the idea being presented. The idea isn't in the text; it's an abstraction of the human mind.

Perhaps better summarized as, "Don't just read: think."