I'm not an expert, but the FTC definitely regulates how emails can be sent (SPAM laws). I'm not sure if the act of creating a list and selling it without the consent of the emailees is regulated, however.

The CAN-SPAM Act doesn’t generally prohibit unsolicited marketing emails, but rather it has various restrictions on the behavior and content of those emails. It’s probably less restrictive than most tech-savvy people think. L

That said, there is a restriction against sending messages to harvested emails, although I’m not sure how that’s defined or what legal precedents there are regarding that.

In the EU it's against E-Privacy