This page explains the semantics of linking and copying primitives.
Primitives (solvers, benchmarks, and jobs) on StarExec can be associated with any number of spaces. To put an existing primitive in a new space, you can "link" it from a space it already exists in to a new space. Linking a primitive simply associates it with the new space-- it does not make a copy of the primitive on disk, and, if you are not the owner of the primitive being linked, it does not make you the owner of that primitive in the new space. Linking primitives has no affect on your disk quota, because linking does not create actual copies.
When a primitive is "copied," a deep copy of that primitive is made both on disk and in the database. This means the primitive will have a new ID, and you will be the owner of the primitive, exactly as if you had uploaded the primitive yourself. The primitive will count against your disk quota. All of this applies even if you were the owner of the primitive that was the source of the copy!
A primitive that has been copied is a totally different object from the source primitive. Editing or deleting a primitive has no effect on any primitives that were copied from that primitive.
Jobs can not currently be copied in any way. Any time an existing job is added to a new space, it is a linking operation.