What is the preferred method of registering a screenplay with the WGA, online or through the mail? Does any particular submission offer a greater benefit?

If you register online, you'll get your registration number right away.  Are you going with WGA East or West?

With the East, you'll get ten years of coverage for $22 instead of five for $20 with the West.

A reminder that WGA registration is only for a few years.  Going through the copyright office lasts for seventy-five years after you've died.


Phil

Quoted from dogglebe A reminder that WGA registration is only for a few years.  Going through the copyright office lasts for seventy-five years after you've died. Phil

This is true although I registered my first script with the Library of Congress and found it to be a pain. You have to wait at least half a year to get confirmation that your script's been registered, not to mention it's more expensive than WGA and you have to re-register every time you change something.

I'd say register with WGA than with the Library of Congress once you have your work in a state you're completely satisfied with.