What is CAN SPAM in Salesforce Marketing Cloud?

The CAN-SPAM Act regulates commercial email messages sent in the United States. The acronym stands for Controlling the Assault of Non-Solicited Marketing.
Here are seven easy ways to make sure you aren't spamming:
Provide an unsubscribe option.
Honor opt-outs within 10 business days.
Use legitimate "from" email addresses.
Don't use deceitful subject lines or headers.
Display your mailing address.
The message should contain at least one sentence.
Monitor your messaging (especially if you contract this out).