A quick survey of the top four ham radio forums via google search shows that that are a number of very popular topic categories. Here are the top common subforums with the most threads (not posts, but individual topics). These are in order of popularity:
- Gear sales/swap/auctions
- General technical questions/elmer
- Specific questions about radios and specific pieces of gear
- FCC, ARRL, Legal
- Bands and modes
- Show 'n tell
- Homebrew, kits, modifications
- Emergency communications
By far the most forum activity was in sales and swap, over half of each of the top two websited was conversations about this, but these are overrepresented because each swap/sale requires its own thread, whereas there are many big threads in other subforums.
I'm not saying this to discount swap, I'm leaving it in purposefully to make sure we understand that a big part of why many amateur radio enthusiasts get together is to try new and different equipment. While we won't support sales and swap here, we can be supportive in a way that helps them swap and sell if we want to.
The next three were fairly significant activities in the forums. General questions about the hobby, specific questions about gear, and antennas.
Following that, activity rapidly rolls off, the last 8 items in the above list account for less than 10% of the activity in any of the forums, added together. I honestly thought show 'n tell was going to be bigger, but I also suspect there's a lot of mixing going on. Someone asks about making a certain contact in the general forum, and a lot of discussion about bands and modes and antennas might occur in that thread. Also note that some forums have an amplifiers subforum, and others don't, some have CB discussions, others don't. The above list is very, very rough and shouldn't be used for concrete decisions, but just a 50,000 foot overview of what the landscape might look like.
I'm not going to draw any conclusions in here, but as you think about it add any thoughts you have as answers, and I'll do the same. There are likely ways for us to increase both traffic and interest/use of the site by targeting the areas enthusiasts are most interested in talking about.
The sites I used were QRZ, eHam.net, WorldWideDX.com, and HamRadioForum.net. If there are other forums that are more popular than any one of these, please let me know.