Many sites show an email signup pop-up when a new visitor lands on their site–
Their logic is sound– let’s capture this customer’s email address ASAP. That way, even if they don’t buy today we can entice them later via email. Here is the trouble– when a visitor first comes to your site they know very little about you (i.e. guards are up), their focus is the search query that landed them on your site. So when you show a pop-up they instinctively close it. You might be better off showing email signup pop-up on their 2nd visit. Don’t take my word for it, test both approaches and see which one generates more signups.