Where do the jobs come from?

The jobs are sourced from the monthly Hacker News post published at the beginning of each month.

How can I post a job?

You can post your job by commenting on the monthly Hacker News post. The Hacker News post remains open for two weeks since the moment it's published. If you want to post a job during the second half of the month, you'll have to wait until the next post is published on Hacker News at the beginning of the following month.

Can I suggest a new feature?

Sure, use the contact form. Bear in mind, this is a side project, so it does not make any money... But I'll be happy to consider any suggestions.