How many domain names do you have registered? I can think of at least five between mine and others I manage. If you were to pass before the registration expired, who would renew them? Remember that domain names aren’t property and you can’t really put them in your will. As I see it, and I’m not a lawyer mind you, there are two really simple options to protect them:
1. Set up a corporation, likely an LLC, and register your domain names through it. You can appoint a designee to take over the corporation and they’ll have relatively few issues gaining administrative control of your domains. In my opinion this plan is highly complicated, but is the most legally sound.
2. For those of us who don’t like to draw up legal documents in our spare time, allow me to suggest a more straightforward approach. First create a list of all of your registrars, DNS providers, hosting companies and the like. Record your usernames and passwords with this list. It’s important that you keep this list updated, by the way, because an old/expired password won’t be of much use. Now, dependent upon how much security you prefer you can either place this list in a secure location at home, or go and rent a safety deposit box at your local bank. Next appoint a technically minded designee whom you trust. Again dependent upon your security preferences, either provide them with the location of this list or specifically grant them the safety deposit box in your will. Make sure to set expectations with your designee and everything should go as planned.
I would suggest that you leave specific, written instructions with your designee. You may also be interested in providing messages for your online communities and friends that he could deliver on your behalf.
One thing you shouldn’t do is provide usernames and passwords in your will. It is a part of public record and can be viewed by anyone. Also, you should probably review your plans with your lawyer. As I said before, I’m not one and this information is provided as-is with no warranty expressed or implied. Feel free to use it as you wish, but my colleagues nor I are liable for any resulting damages.