As I dont have any experience on the machining hobby side of shows and advertising.. my input is limited in that area.
However the Mazda Forums side I have been a part of for a very long time.
I think something interesting happened on the Mazda forums.... as they are for the most part Catering tot he Rotary.. there are a few sites devoted to them.
The largest is the RX-7 Club. Tht forum was for a long time the largest automotive forum on the net. (long ago passed I gather) and it had a huge ton of members, and a handful of advertisers, mostly comprised of the owners of the forum advertising thier own race shop, and covering the cost of the website and bandwidth hosting.
Over time though.. the very knowledgable posters who didnt post a lot.. got overrun by the "kids" in the lounge section who posted 234896 times on every single comment made by anyone. Then when there was a technical thread, the new kids would see that person with 348925387 posts chime in, and make the fault assumption that they know what they are doing, because they had read a lot of posts, and or were some sort of guru.
As time has passed and Forums on the internet have become commonplace, people have learned to read posts for content, not post counts. And Im talking about progression of the average forum reader covering more than a decade.
So another thing that happens... the knowledgable people get tired of arguing over semantics with some know it all high post loudmouth.. so they form thier own forum.
These come in two flavors.
Those that survive and those that dont.
Those that survive seem to have a core membership of knowledgable people who post eregularly, and a smattering of semi-regulars coming for advice.. and learning the right way to do things. They also have a random number of completely clueless people who show up and ask silly questions... 50 percent of those learn something.
Those that dont survive either have a handful of members who end up fighting and all leave. OR.. the people who form it do it out of spite for the board they came from.. and eventually end up lurking on the original board, or leave the hobby all together.
The only things I know that have hurt a forums are a couple things...
Ads that highlight words in everything and have popup things that drive everyone nuts. Lots of people leave forums from those things. (watched it happen)
Selling the forum to a management company that doesnt know the hobby. This is bound to cause a world of problems because you have admins who are paid to be on there, and could care less about the people on the board. And they ALSO dont have a clue as to who is right or wrong. They just wield a ban stick like a scythe.
Overly hyping a forum. By overly hyping, Im referring to what noe of the Rotary forums did about 5 years ago that lost them a TON of members. They were a smaller forum.. btu building a solid membership of hardcore techinical resources. The young college guys who started it decided to make purple shirts with a hideous logo, and they had all sorts of slogans... slamming the other types of engines and car makes. AS WELL AS FORUMS. They gave these shirts out to a large number of members who attended a very large car event, as well as talked a lot of trash openly about all the other forums to everyone at the event.... and the backlash was HUGE. A LOT of people deleted forum membership as they didnt want to be associated with the forum.
As far as shirts and logos and banners, and or advertising... I think the youtube links people make.. the links the site gets picked up from Google etc.. is a good start.
If there was a profit to be made.. I would say advertise in any way possible.
I think this forum will be a oak tree of a forum. It will continue to grow with content, and projects, ideas, and new members who also continue to bring in new projects and ideas.
The methods being used to make things are all the same. THe projects are always going to be similar.. but the flair for turning them out, and or the way in which they are cobbled together is what makes the Madmodder portion.
Otherwise this would just be another pigeonholed forum catering to one specific thing. We have wayy too much variety for that.