Honestly, the internet presence (sheer volume of sites) and ease of start up in PA was what initially led me to join NACHI.
I have not had as much success as some seem to through findaninspector (2 calls in over 2 years) so the internet presence panned out to be much less than I had hoped (not criticsm, just honest feedback since it sounds like you are looking to learn what to advertise to whom).
In my first year, the inspection illustrations (I think they were the CArson Dunlop ones) were a huge help as a reference and for report writing. They have since gone away, and the newer version is not indexed so as to be useful (again, not a criticsm, just feedback on what I used as a newbie).
Through the BB (most notably Russel Ray) I got a lot of information on marketing that has been the single best thing I have done for my business. If RR writes a book - I’m buying. If he recommends a tactic - I’m trying it. And if he starts his own association - I’m joining.
The marketing section of the BB is what I use most frequently now, and the tech threads are great for fast nuggets of info.