It’s Canada Day, and this year it has special connotations for email senders who are in Canada or sending to Canadian residents.
CASL is now in effect. For in depth guidance, go visit Matt Vernhout’s excellent series on CASL.  But for those of you who just want the Cliff notes here’s the high points
If you are in Canada or you are sending to residents in Canada:

• You must have consent to send email.
• Implicit consent (similar to “prior or existing business relationship”) expires after 2 years.
• Explicit consent does not expire.
• Checkboxes on websites where addresses are collected must be unchecked by default.
• The sender is responsible for keeping records related to how and when consent was obtained.
• Even transactional mail must have an opt-out link.

In terms of enforcement, senders have 18 months to send to implicit opt-ins and then those addresses must be retired. During those 18 months, however, the implicit opt-ins can be transitioned to explicit opt-ins. If a recipient makes a purchase then the implicit opt-in clock is reset from the point of the purchase.
CASL does provide for private right of action, so individual recipients can sue senders for violations.
Overall, CASL is a reality and anyone mailing to Canadians needs to pay attention.

CASL