The Internet has been growing so rapidly that it has become a primary tool for people to look for information! Simple as it might appear!
Some categories of information, such as obesity, male impotence, debt, getting rich, MLM, etc., are considered to be so sensitive that people would not discuss with their folks offline. They'd rather go online and search because they know the virtual world will protect their identity and save them from shame. In other words, the Internet is the place for people to look for solutions to their problems. If you know how to target certain groups of people who are willing to spend on those solutions, you've made it!