Most probably you know this feeling. You open up a new web page and half way through reading the content on it but suddenly you’re interrupted by a huge overlay asking for your email address. In most cases, your immediate reaction will be either to close overlay or to close an entire page with this overlay. The reason why so many sites are using this technique is obvious. However, the technique has a huge negative effect on user — it asks the users to stop doing what they’re doing (what’s important for them) and focuses their attention on completely different activity (what’s important to you). It’s better to allow users to finish the current activity (e.g. read content and get acquainted) before asking for anything. Give them the chance to decide whether or not they want to do something on their own instead of forcing them to do it.
The main downside of the technique is basically it’s major advantage — there’s no finishing-line in sight. When users get to a certain point in the stream, they can’t bookmark their location and come back to it later. If they leave the site, they’ll lose all their progress and will have to scroll down again to get back to the same spot. This inability to determine the scrolling position of the user not only causes annoyance or confusion to the users but also hurts the overall user experience, as a result.
In 2012 Etsy had spent time implementing an infinite scroll interface and found that the new interface just didn’t perform as well as a pagination. Although a number of purchases stayed roughly the same, user engagement has gone down (people weren’t using the search so much).