The most easiest and effective method of earning money online is by having your existing customers spend money multiple times. A lot of us spend a great deal of time and effort on trying to attract new customers that we neglect the ones we already have. In more simpler terms: "it's easier to have a customer make multiple purchases, than having them spending money once and then you having to find a new customer".

One of the best ways of getting your customers to spend money multiple times over a period of time is by tracking their details using a mailing list. At some time over your Internet experience, you would have been asked to input your name and email address (or additional details) into text boxes, especially when signing up to a website or online newsletter. The primary reason for this is so the owner of the website can keep in contact with you, and perhaps email you multiple offers so they present an opportunity for you to spend money on their products/services.

It makes great sense though doesn't it? If you purchased a product and was very pleased with the product, if that same website emailed you a similar product in the future, there's a good chance you will at least consider buying the new product, because 1. You trust the website and 2. You know the kind of quality you can expect due to the previous product you bought.

So essentially what a mailing list is a service, which allows you to capture visitor's details by providing you with code that can pasted into your web page. Once a visitor has submitted their details, they will then be "subscribed" to your mailing list, and are able to unsubscribe at any time if they wish. However these mailing list services also provide you with another huge service and that is bulk email. As mentioned previously to continually keep in contact with the visitors that have submitted their details, you'll be using email to contact them. If you had 5,000 visitors on your mail list, it would be a huge pain to individually email them and make your additional offers. What mailing list services do is allow you to write 1 email and have it sent to everyone on your mailing list at once with a click of the mouse.

Although it sounds like a great way to increase your sales, you may have some trouble getting visitors to submit their details. With the large amount of spam these days, you should offer an incentive for them to input their details and also make it clear what they're signing up to.