The phrase "post opportunities" means to share or advertise available chances or openings for something, such as jobs, internships, or projects. Full definition
My Blog Guest is a good place for those who plan to accept guest contributions on a regular basis or look for guest posting opportunities on popular blogs in various niches. (philosbooks.com)
Provide guest post opportunities for authors on your blog if you have one. (paidauthor.com)
If a blogger is getting paid trips or really great sponsored posts opportunities they are working very hard to achieve that. (thesitsgirls.com)