More specifically the check if it's an imgur.com link

As they are images, always available, quickly loaded, imgur links kind of optimise the thrill/time factor

For super-optimal Reddit viewing speed, use the HoverZoom Chrome extension: https://chrome.google.com/webstore/detail/nonjdcjchghhkdooln...

Then you don't even have to click the link to see cat pictures, you just hover and move on when it's not very funny.

Also youtube videos.

They also skip right over the sponsored link.

They can't even view the side ad.

of course the truly experienced user will have ad-block

The data in the article does seem to bear this out. The source domain is displayed at the end of each headline, which probably accounts for the shadowy spots on the right side of the veteran redditor heat map. You really only need to glance at the end of the title to see if it's an imgur link or not.