I admit, at the beginning, I really didn't understand the point of having a mailing list.
I'll just send them through my website and get them the first time.
While you can do that, the percentage of people who will buy from you the first time is very small.
So small it's a small wonder you can get a sale at all.
That sale is dependent on having a good ad copy and product as well.
It all has to line up and work.
A lot of new marketers don't understand how important it is to build your opt-in list as you also perfect your sales page.
I think it's even more important if you are using paid traffic to get people to your site.
Since you are now paying for that person to come there you need to do the best you can to get that sale.
If they click your ad and land on your site, but click away without buying you've lost a potential customer and some advertising money.
Since you can't keep everyone from leaving, you've got to have another way to keep that visitor somehow.
Here we have the opt-in list.
By having a visitor give you their contact information, usually a name and email address, you can now stay in their heads long after they've left your site.
You have a better chance to sell to them later.
You may end up selling them an affiliate product and not your own.
If you had not gathered that visitor's email address they would have been lost and never seen again, but since you have it, you have a shot at selling to them and keeping them later, as well as building trust in you that you know your business well enough for them to buy from you later.