In the US, if I release a video game (or other digital work) online do I need to send a physical copy to the Copyright Office?
Not unless you also released it in physical form. First, you don't have to send anything to the copyright office; registration is only required before you actually file an infringement lawsuit. Second, when you do register, the Copyright Office says:
What works may be registered with electronic deposits?
The following classes of works may be registered in eCO with electronic deposit copies:
- Unpublished works;
- Works published only electronically;
- Published works for which the deposit requirement is ID material (see the Special Deposit Requirements section of Circular 1 for more on ID material);
- Published works for which there are special agreements requiring the hard copy deposits to be sent separately to the Library of Congress.
All other classes of works may be registered via eCO (application and fee payment) but require hard copies of the work(s) being registered.
Under part 2, if it was only released electronically the USCO will take electronic deposit.
It depends on the nature of the digital work. See one (or more) of the following: