Observations for a directory site
1. Information about the industry & a directory
2. For sale (used equipment)
3. Wanted to buy (equipment or parts for older models)
4. Help Wanted
5. Seeking a Job
I don't know how difficult it is to set up a site where people can create their own content, but these sections do seem to get a lot of traffic.
You can, of course, sign up for the mailing list, and there is advertising on the site.
Might be an idea for added value for a local niche site.