On Factions server, players group up in Factions. You claim land as your own and build your base. Factions is a self serve anti griefing system. Leaders control who can can edit their faction land.
Factions is also about diplomacy and war. You declare wars and forge alliances. You fight over land and manage your monetary expenses.
Basic commands (full list in /f help)
/f f - show faction information
/f p - show players information
/f join - join faction
/f create - create faction
/f leave - leave faction
/f invite add - invite player to your faction
/f invite remove - remove player invitation
/f money - manage your faction money
/f claim - claim land for your faction
/f unstuck - teleport to nearest wilderness
/f tax - manage faction taxes
/f disband - disband your faction
/f flag - manage your faction flags
/f perm - manager your faction permissions
/f enemy/allay/truce/neutral - set faction relations
/f sethome - set faction home
Is there ObsidianDestroyer plugin?
Yes, you can use Stick to check Obsidian durability.
Are chests protected by faction plugin?
Is raiding and TP-killing allowed on Factions server?
Yes, unless you're asking staff member to help you with something (that's the only case when TP-killing is not allowed on Factions).
Is there mcMMO on Factions server?
How can I exchange / trade stuff with other players?
You can use /ah or /trade, but keep in mind those commands won't protect your against PVP.