I don't think it would fly.

Your market is basically "new forum" owners.

Majority of them are novices and hobbiests.

The ones that are seriously setting out to build a professional community, likely already know the "top of mind" places to run to such as Fiverr.com, Freelancer.com, 123Employee.com or would just hire a team of their own.

Also ... get paid to post programs exist.

The group you could even potentially sell the service to is far too limited and isn't "hungry" and "rabbidly searching" for such services... so each sale you make, you'd have to hard-sell.