“I wish I had a smaller email list…” said no one ever. Quality is key, but sometimes sales is strictly a numbers game. A qualified lead is more likely to convert, and more quickly, but how much qualification should you do up front, and how much can come later? If you are looking to build a strong list, opt-in advertising offers an affordable way to grow your database at scale. How fast, how big and how finely tailored? That’s up to you. Here’s how it works.