I live in San Francisco, CA, USA. Ballots here are also serialized and many (most?) people vote by mail which means that serialized ballots are mailed to you s

I live in San Francisco, CA, USA. Ballots here are also serialized and many (most?) people vote by mail which means that serialized ballots are mailed to you specifically at your registered address. After the vote, you can check the status of the ballot's serial number at the appropriate city/county website. It won't tell you who voted or the votes cast, but that it was received. So while the website won't link you to your votes, the city/county could absolutely make that connection since they control the serialization and the mailing. One hopes that they don't do this, and I'm sure they're not suppose to, but trust and wishes are the best surety we have for vote by mail ballots... there are ways to defeat the loss of anonymity in this case, but they involve not voting by mail or providing false signals (i.e. swapping ballots with someone else in your district).