An excellent question, the answer is "it depends".
The cost of using our service goes up based on the number of email addresses you have. For every email address you have, you consume one token per month. You can earn tokens to keep our service free by placing text link(s) on your webpages to our website.
The value of the link is determined by our proprietary ranking system. A link's token value is determined by the importance of the webpage where you place the text link. A webpage that receives a lot of traffic has a much higher value than a family photo page that gets only a couple of visitors a month. If you have a webpage that is private, password protected or does not receive any visitors that page would not earn you any tokens.
Once you register for our service you will have access to a licensing page where you can enter a website URL, and our systems will evaluate the webpage to determine its value. The higher the importance of the webpage, the more licenses you obtain by placing a link the page.
Most of our clients are able to able to get all their email addresses protected with one or two text links. For users who are not able (or willing) to generate enough tokens every month using text links, tokens can also be purchased.
Links must be visible at all times by all web site visitors; links cannot be hidden with style sheets, javascript or any other technology.