I'm working on improving our opt-in process and I think it's best to have a checkbox on landing pages for people to opt-in to get email communications.

However, a colleague says it's just fine for people to click a link and clicking the link (with something like "for more information, click here") counts as an opt-in.

Is anyone familiar with email compliance laws internationally?

e.g. in Europe/Canada?

Or do I need to add a checkbox for people to explicitly opt in, for countries requiring double opt-in?