I tried to find out what people like and want online by checking out the big sites that have a lot of visitors. There are a few categories. One big categoriy are blogs and sites that encourage visiter participation, such as political blogs and newspaper letters to the editor. These sites get huge traffic numbers and make millions yearly on selling advertising.
Another major category of large traffic websites, a category that has interested me (I am a collector and analyst by nature) are the ones I call “reference” sites. Dynamic database sites, mostly. The best example I can think of right now is the huge movie database site IMDb dot com. You have probably visited it. If you are a movie person, this site has answer to every movie trivia question you might ever have.
There are database or “reference” sites on just about every category you can imagine. I found one the other day on Greatest Trials in History. I like crime, criminals, trials. There are other database type sites on the American Old West, for example. The old gunfighters and like that. And sports sites, info on every baseball player or boxer you can imagine. Some of these sites are slick dynamic sites (where the visitor can enter his own additional data about the subject, like editing wikipedia or adding bio information on the movie site) and some are just plain websites with page links. Many are blogs. You can do a lot of info with blog posts on various trials or crimes or gunfighters or recipes. Databases, more or less, but a reference library too.
If you have a good one, an interesting subject, you will get lots of visitors and lots of links and lots of repeats. Then you can sell adverts, either general or specific to your subject. I would think you could make some money by running even a very specilized niche database site. Of course, if you are not into research or learning new things all the time, then this would be boring for you to collect stuff. I wouldn’t recommend trying to set up an info blog or site on a subject you are not really personally interested in.
But that still leaves the question of how to get traffic initially. I don’t know how to get traffic except through advertising. Commenting on other blogs is advertising. Using the proper words in the title to your page or the title of your post is advertising. So are proper labels and the use of keywords in your blog body or site article. Of course, advertising can be purchased, but, except for adsense, perhaps, I would wait a bit and try the free ways first. “Free” means getting more and more traffic because Google sends it to you. In that sense, your own writing and layout and attention to words are your best advertisement.
Have enough good, interesting stuff to bring people back. Think of some subject you like, then think of some type of reference material related to that subject that would make people want to check back frequently.
Making money with a website or blog is a matter of thinking of ways to get large numbers of people to visit you. That needs to be your primary goal. If you want to be successful at making money online, spend time researching the ways other people are using to get people to visit. Make sure your site is interesting so when they get there they will want to stay a while and want to come back. Be interesting. At least to your niche audience.