Do I have to register to vote in California by law, or do I have a choice not to register? Just a little confused over here?

Just as it says, if you wanna vote you gotta register. Following up to 'encourage compliance'--I don't know what that means, and I agree it sounds little ominous. I think it just means you get a letter or a phone call asking you 'Don't you want to vote? Register now!'

Are you sure it came from somebody official? Most election authorities I know in my state wouldn't dream of phrasing a letter that way. Of course, California is a little bit bigger on encouraging people to vote than in my state where the legislature would prefer that the average person didn't vote.

That sounds like something a candidate or political party might send out, not a government body. Is there any thing on the letter indicating who sent it? If you want to vote in elections then you need to register.