Steve,
I think it is that this site is not any different from the many, many amateur radio message boards out there and that this board is only a couple of years old, so it was created too late to gain any foothold on the internet market. I'd say the two most popular ones out there are qrz.com and eham.net.
When I first happened upon this site I had a chat with the creator and suggested that to stand out from the others, this site would need a different format. Instead of the usual topical message boards, I suggested message boards divided by geographical location. Either for each state or for each call district and one for DX. Sometimes there are issues or events that not everyone needs to know about. For example, take a ham-fest in Iowa. I'm sure a ham in California wouldn't care about that.
I have looked at other amateur radio message boards and even though there is more posting going on in some of them, it always seems to be by the same people for the most part. (Same goes for some of our local topical neighborhood message boards.) So, possibly with the increased popularity of the Web2.0 sites like Facebook, Twitter and even ham related Web2.0 sites like 73s.org and hamradionation.com, message board sites like hamradioparadise.com are seeing a decline in active members.
You want to see a site that's even more deserted? Check out
http://www.hamradiotalk.com if it's still there.
I only post normally when I have an announcement like a ham-fest or testing, etc. I figure if I have time to be on a message board, I have time to be on the air. (Of course I'm at work right now so that don't count.)
If this site were mine and it was costing me money to keep it online, I'd probably shut it down.
Anyway, that's my opinion.
73's!
Tom N0LOH