If “Lead Flow” is Hub Spot’s term for popups, the context for testing popups should be obvious: Anything that can lead to more signups or engagement with leads needs to be explored. For instance, is a % off for new subscribers as strong a case as $ off for new orders? Is “Free” better that “Information” or “community”? There are so many variations to test in acquiring a new customer and no best practice is a best practice for all potential customers or for all merchants. Do you need more examples? Hope this is going to move up in the proposed or actual feature enhancements for the Lead Flow system.