fsgw2.org is a free-to-nonprofits virtual server, provided by DreamHost. Actually, it provides multiple virtual servers, one at the base domain name of fsgw2.org, and others at subdomains of our choosing, for example: wiki.fsgw2.org, wp.fsgw2.org, and wff.fsgw2.org. We don't know of a limit on the number of subdomains. The de-facto limit is how many we have the time and energy to set up and maintain.
A huge benefit of having multiple virtual servers is that the software installed on one does not impact the others, for example: wiki.fsgw2.org has DokuWiki installed, wp.fsgw2.org has WordPress installed, and wff.fsgw2.org has some FSGW developed software to support WFF. Each package can put its page tree at the root, avoiding contortions to accommodate multiple competing page trees on one (virtual) server.
FSGW wiki, using DokuWiki
More information about the wiki
More to be added here…