I follow, but how can one tell from looking? There is a convenient "[pdf]" tag when a link is a PDF, but no indicator besides missing controls that there is some special arrangement for job postings. I had to check the web to find out that Optimizely is YC-funded, and I had no idea YC jobs had special promotion on HN until I found this post. It's a slightly shady thing to do without any obvious indicator of what's going on.