It is a good way to build a reputation as long as the information or training is of the best quality. A blog is good but you need something to remind them to keep coming back. There are some excellent examples around of incentives and reminders mailing list used by bloggers to get customers to check regularly for new posts. Special reports are great, especially as an introduction to another product. One method that is becoming popular is to offer the first few chapters of an e-book and then get the customer to buy the rest.
An ezine or newsletter is the best option for building a relationship with your subscribers. If subscribers find your information interesting, entertaining and valuable, you will be able to sell them so much as they will trust your opinion because mailing list they will feel you are a friend, not just another marketer. One of the biggest differences between those who make it online and those who don't is that those who do are testers. You see, not everything you see or read online will work, or work for you.
But if you do ten things, spend $200 and bring in $200, you have only broken even. But let's imagine that you spent $20 on each of the ten sources of advertising, but only two of them produced the $200 return. If you had only spent the $40 necessary to advertise in those two places, you would be ahead by $160. If you had tracked where mailing list every subscriber and sale came from, you would know where to spend your money the next time around. You should have an auto responder with unlimited accounts.