Alter Aeon Online Help

Keywords are:  'clan areas'

Clans have by default a clan area, consisting of up to 20 rooms.  If the
size of the clan becomes big enough to warrant a larger clan area, more rooms
may be purchased using in-game credits.  See 'help donations' and
'help credit buy' for more information on credits and donations.

Note that having a clan area larger than 20 rooms will raise the dues
required for your clan.  Above 20 rooms, each five rooms raises the
dues by one gold per tick.  If you're an elder, you can get a breakdown
of your clan cost with the 'dues' command.

Note that having a clan web page can reduce your clan cost tremendously.
See 'help clan discount' for details.