Ads/ Promoted posts on HN front page?

It is interesting to me, given the age of your profile, that you just noticed this. I'm about as old as you are, and its been noticeable for a while and happens frequently.

If you click the "jobs" link next to "ask" and "submit" you'll see a filtered list of links including the one in your screenshot.

You must be new here. YC companies get limited advertising.

Treskot's profile is four times as old as yours.

The job postings used to have upvotes in the same way that articles did is probably why the OP is questioning this.

Yes. YC companies are allowed to frequently submit job postings. They start out at the top of the front page and decay at a fixed rate.