Hmmm,
I just signed in for the first time in maybe two years. It's a hassle to visit that forum. There is no cookie for login retention, so you have to log in manually every time...user name/password and one of those word verification thingies.
Ah, found it. It seems the site is broken and they lack some admin functions; and progress to fix is very very slow. Looks like they locked everything down to keep out rampant spammers. There is a message up from April saying they were going to upgrade, but I guess that either didn't happen or didn't fix the issue.
So, they aren't excluding people...it's not that they won't let you sign up, it's because they
can't let you sign up.
You might like:
http://www.45watt.com/http://www.ppwatt.com/http://www.sewatt.com/These are all sister forums to 18watt, but run on different software. And I believe if you register on one of those three, you're set for all three.
I prefer Weber's forums...
General
http://www.tedsforums.com/forum/index.phpKits and DIY
http://www.weberorders.com/forum/Metro's Forum is THE resource for JTM45's and Plexi's.
http://forum.metroamp.com/But the best may be this forum...
http://music-electronics-forum.com/It's what Ampage became, and Ampage was the grandpapa of all DIY amp and pedal forums.
Then there is "the forum that shall not be named." That's a bit of a running joke, a pedal maker (for whom I have the highest regard) once went on a rampage about it without naming it, and it stuck It has a little amp stuff, but is mostly pedals.
http://www.freestompboxes.org/