Let say you are losing hair and you are researching the topic online. You will probably read everything you can find. If you then get a pop-up offering a free g

Let say you are losing hair and you are researching the topic online. You will probably read everything you can find. If you then get a pop-up offering a free guide on natural remedies against hair loss, you will definitely want that. Granted, the guide needs to deliver some value and not just be a bait and switch. If it doesn't deliver any value, it's pretty much guaranteed you will lose that subscriber. To give you a real example: I offer a guide about design patterns and most of my subscribers come from that pop-up. And they are developers, showing that while pop-ups are not popular on places like HN, they are definitely not despised by all developers. I myself sing up when I find something I am interested in. For example, I got a nice free guide about photoshop blend modes which was very useful when I got it.