A regular "Who Is Hiring?" thread appears on the first weekday of each month. Most job ads are welcome there. But only an account called whoishiring is allowed to submit the thread itself. This prevents a race to post it first.
The other kind of job ad is reserved for YC-funded startups. These appear on the front page, but are not stories: they have no vote arrows, points, or comments. They begin part-way down, then fall steadily, and only one should be on the front page at a time.
not op btw