Who can join?
Anyone who is interested in retro-roleplaying, especially Basic D&D/Labyrinth Lord, but especially if you live in Vancouver and want to join us for a game. But really anyone. If you just want to hang out on the forum and talk Red Box, go for it.
Membership has its privileges, but it's not really necessary to participate in the site.
update: Thanks to spammers, you now have to join the site to use the forum, edit & create pages.
If you join the site officially, you can also rename/move pages & upload/delete files. It also makes cr0m happy, because he can look at the list of members growing and get a warm fuzzy feeling inside.
At meta-gaming level, anyone who registers for a wikidot account and proves it by posting in the forum gets 100xp for their PC. Ditto for making substantive additions to an adventure summary (DM's discretion as to the definition of "substantive").
You need to have a Wikidot.com account and be signed to apply for membership.
if you already have a Wikidot.com account
it is worth it and is free
Also, cr0m doesn't often check for membership applications, so if you applied and it's been a few weeks, post something at the forum bugging him.