Flowgo practices opt-in by deceit on the card sending sides. When you send a Flowgo card, you input your email address and at the top of the form. At the bottom of the form, you see this....

bottom of the Flowgo card send form

You will notice that several of the boxes are already checked off. What this means is that if you send this card, you can if you are not careful fall into an assortment of unwanted newsletters. Technically you have subscribed, but this is slimey.

Your recipient is no longer trapped by Flowgo, but recipients often turn sender, and if they do, they risk falling into the same trap. Do you want to accidentally entrap a percentage of your card recipients?