The three phases of email marketing are One: Obtain a customer via an opt-in form. Two: Welcome and thank your new customer for subscribing to your list. Three: Follow-up on a regular basis with new valuable content !
The advantages are many. Someone has given you permission to send them updates on your goods and services— in fact they are expecting to here from you ! You cannot do better than having eager customers looking possibly to buy.
The answer is yes ! You need a service like the one I use on a daily basis.
Once someone opts-in to your newsletter you can send and automated welcome email through what is called Marketing automation. You just create the type of welcome email you would like to send and create it and send !