They want you to subscribe.

Because subscriptions or email marketing gives pretty nice return on investment (ROI) most of the web admins use extreme measures to capture users attention to users can potentially subscribe.

There is a huge controversy on how to best pitch your users to subscribe to a newsletter. Apparently, displaying a delayed popup does a good job than other methods or just displaying a subscription box in the sidebar. Or maybe the webmasters are not testing at all which works better.

They want you to subscribe.

Because subscriptions or email marketing gives pretty nice return on investment (ROI) most of the web admins use extreme measures to capture users attention to users can potentially subscribe.

Pop ups work well for increasing email subscriptions

They may be annoying but surprisingly, they work very well specifically for gathering email subscribers. There is a huge controversy on how to best pitch your users to subscribe to a newsletter. Whether the popup should be displayed when the visitor enters the site, or when she leave's it, or when n amount of seconds has passed. The important thing is to display it at the right time when users are more likely to subscribe on your particular site. The best thing to do is do user tests and try to identify when users are most pleased with your site/app and then fire the pop-up.