You can create a claim over your base or a specific area to protect that area from griefing or players being able to basically do anything in that location.
/claim: toggles you into claiming mode
Claim Modes
/basicclaims: selects Basic mode (default)
/subdivideclaims: selects Subdivision mode /townclaims: selects Town mode
**/cuboid: **works on top of all other claim types, makes 3D claiming
/townclaim: claims a town claim (one per player)
/claimtool: deactivates and activates the claim tool (a stick). Can be really useful if you are using sticks a lot.
Remember that to claim in subdivide, you have to /subdivideclaims and the toggle /claim to be able to claim.
You can learn about trusting people in your claims here