Building an email list for people who trade forex would be done the same way a list is built for any niche. The most common list building methods are: 1. Have a basic niche website on that topic 2. Offer something of value for free (a special pdf report) 3. Drive traffic to your site 4. Get visitors to opt-in to you mailing list 5. Build a relationship with the list by providing useful information on a regular basis
Traffic generation can be done through various methods: 1. PPC traffic - sending traffic to a landing page using a PPC engine (can be expensive to build a list like that). 2. Article marketing - writing relevant articles and distributing to article directories and linking back to your landing page that has the mailing list opt-in box 3. Classifieds - was used more in the past but can still deliver some targeted people 4. Offline advertising - taking out an advertisement in a paper/magazine/radio show that is targeted to your audience (can be expensive as well...). 5. Printing up flyers and getting them delivered to households There are many other types of marketing you can use to drive visitors to your site. You need to know where your potential list members hang out (which sites they currently use etc) and then contribute to those communities and build up status. There is no sense just driving untargeted visitors and definitely avoid paying for any traffic that promises 100,000 unique visitors (that will not be targeted).