If I may add my $.02, the popup ad is intrusive, but I understand the need to generate revenue. My objection is the frequency that it appears. On some of my visits here, it has appeared on almost every single page load. It appears to be set to come up at random, with no limit on the number of instances. I was hoping that might change when the prior offer expired, but the new one is just as bad. It's a nag, like a salesman following you around a store, continuously asking if you need help no matter how many times you say, "No, thank you." For many people, that kind of nagging will drive them right out of the store. Same applies here.

Is it possible to limit how many times the ad appears within a session? I'm a former web developer, and my approach would be to set session variables (cookies that expire as soon as the visit/session expires, usually 20 minutes by default). The code would display the popup on the first page load and set a counter. Once a specified number of popups had displayed (please, no more than 2 or 3) it would stop. It could also count page loads between popups, allowing a minimum rest of say, 5 page loads before displaying the popup again.

I think limiting the number and frequency of popup ads will help this site promote more subscriptions without driving away potential customers.