Whats to stop Yahoo from exposing our true identity?
Read Yahoo’s privacy policy. Basically, the only reason they’ll turn over your identity is if there is a court order that forces them to do so. You can send email from sites outside the US which don’t respond to US court orders but frankly, I can’t imagine anyone using OpenNIST for something that’s going to involve the courts. (As the OpenNIST description says, use the DoC Inspector General for things like accusations of fraud or embezzlement.