Your ownership of an unregistered copyright is every bit as legal
and binding as your ownership of a registered one. However,
registration establishes a public record and affords the author certain
legal protections and remedies that might not otherwise be available.
Registering your copyright before your work is published, or within
five years of publication, creates a legal presumption that the work
belongs to you. A presumption cannot be overcome in court without
compelling evidence. Further, having registered your copyright before
any instance of infringement entitles you to statutory damages and
attorney's fees in the event you prevail in court. If the copyright
wasn't registered prior its infringement, then any award would be
limited to actual damages - i.e., the amount of money the infringer
made on it, with no added penalty for wrongdoing and no reimbursement
for your attorney fees. In any event, you must register your copyright
before you can file an infringement lawsuit.