I admit, I've always had an instinctively negative reaction to pop ups asking for your email address. They're often badly designed, appearing before you even know what the website's content is about. When they are too persistent, or get in the way of my reading experience, they can be enough to make me quit a website in a dramatic huff.
However, they work.
Yes, those irritating call to actions (CTAs) work.
I know this because we've started using one on this very blog for a week and a half, and in that time doubled the amount of people signing up to our newsletter via our website.
Email marketing is one of the most valuable marketing channel there is, so anything that can help it grow is a good thing.
We've used Mailchimp's own pop-ups which integrates seamlessly with our Mailchimp newsletter list, but there are plenty of other providers out there, such as BuzzSumo which offer similar options.
The article below shows similarly positive results with pop ups.