If relevant, you can set up a jobs page that displays job vacancies from within your niche. You can then charge companies to list their job on your website. A perfect example of this is within Inbound.org where they allow you to post online marketing job vacancies for $50 a month per listing.

Advantages: If you have the right audience, companies will often pay a significant amount of money to list their job vacancy on your website.

As well as this, you will often have other ways to monetize the job section of your site through things like banner advertising, etc. so there can be multiple revenue streams from having a job board in place.

Disadvantages: There's a lot of upkeep involved with both setting up and maintaining a job section. Alongside this, you will need to invest in driving traffic through to the job section of your blog in order to deliver ROI for your advertisers.

If there isn't a big demand for this within your niche then it might not be commercially viable for you.