Answer:
If you have me you want to share me. If you share me you don't have me. What am I?
I am a caribbean shape that makes ships disappear
By myself, I'm practically nothing. Worthless as a leader, but when I follow a group, their strength increases tenfold. What am I?
You can always find me in the past. I am created in the present, but the future can not change me. What am I?
I am made by nature soft as silk; A puffy cloud white as milk; Snow tops this tropical crop; The dirtiest part of a mop.
Though not a plant, has leaves. Though not a beast, has spine. Though many wouldn't need this thing, It's more valuable than wine.