I've decided to ask this question here, as there is no better StackExchange site to ask and it's also not that much off-topic for OnStartups.
I'm from Europe and I signed (by email) IT service contract+NDA with a California-based corporation (Inc.). The contract can be terminated by "written notice". That term is not defined in the contract, so I suppose that California and/or federal law applies.
I scanned the statutes listed here, California Civil Code, rougly took a look at monstrous California UCC and although I think that written notice by email should be perfectly ok, I'm lost at the whole matter, especially that I'm used to continental law, not codified common law.
The federal "Electronic Signatures in Global and National Commerce Act" legislation says it's OK unless (...) UCC is involved, UCC seems to not cover my case, and California Civil code says that written contract should be changed in writing, but also that using electroning means is ok if both parties agrees on that So:
You can send certified mail from anywhere in the world, it's all standardized. You will receive an acknowledgement from your post office (ask for the option when you send the mail). This is the most bullet-proof option.
In practice, as long as you can show that you gave notice, and the other side received it, any judge will agree that it's good enough. So if you want to save on stamps, email and fax them your notice and ask them to confirm by email that they received it. Unless you are in a highly conflictual situation, they should oblige. Then you're good.
My problems with e-mail notice are (a) one cannot be sure whether it suffices legally under many circumstances and (b) perhaps more important, one cannot count on receiving a confirmation that the addressee received the notice.
I vote for an international courier, such as FedEx or DHL, that provides confirmation of delivery that you can verify online.
Disclaimer: This information does not constitute legal advice and does not establish an attorney-client relationship.