In reply to Steve Wilkinson.

I see what you mean @Terence and Steve

> I think you will understand why this kind of interrupt marketing is not a good idea.
Thanks for the link, it is worth reading.

> Do you prioritize UX or marketing tactics?

I prefer user experience and i am not working with popups either.
Not because of any principle aspects but rather the risk of leading away of my audience I am selling software products and not informations so a popup would "interrupt" my customer and possible prevent him from checking out so i agree with you here.