It was a lovely design idea, but I found it distracting as I was reading. A bit like how a running video elsewhere on the page draws the eye, the cogs moving as I scrolled distracted from the text.

If they just were behind the title and opening paragraph, they would scroll out of view relatively quickly. You'd get the nice effect, but stop being distracted.

Spinning cogs in the background?

Didn't even notice them, so I clicked back to the article. Sure enough, there are spinning cogs.

Didn't notice them, no distractions.