Your listing in the directory
ForumSpark runs a public directory of communities, and being in it is free discovery: people browsing for a community like yours can find you without ever having heard of you.
yourboard.forumspark.net/admin/directory
Overview, then Directory Listing.
Getting listed
In Overview, then Directory Listing, switch the listing on and shape your entry: the category your community belongs to and the description a browsing stranger sees. The description is your shop window, so write it for someone deciding in five seconds: who is this community for, and what's alive here?
Or staying out
The listing is entirely optional. Private communities, invite-only spaces and boards that grow through their own channels can simply leave it off; nothing else changes.
If you list, revisit your description twice a year. Communities drift, and the entry that described you at launch usually undersells you by the first anniversary.