One topic I'm getting into a lot in this blogs is different online venues that allow writers to post and promote their own work with the potential of making money. Again, each of these places do things a little differently. On Associated Content you have several publication options, which includes upfront payment under some circumstances. On Hub Pages, the writer's earnings come entirely from ad revenue, and to make a little money you will have to sign up for those different services and activate them on your Hub pages account after you have posted several good hubs. AC is more journalistic, but hub pages can also get a lot of traffic and has a fun and artistically appealing interface for creating your 'Hubs'. Helium is another website that allows people who like to write to earn money from sharing their work.
It is possible to write for all three of these places, and several others, at the same time. It should be noted that to do it well you're not going to be able to focus on three or more at once unless you have time to treat it like a full time job. Over time, if you experiment with several and link some of your work together, you will up your traffic and earn more. If you are not already doing this and want to try one to begin with, I'd suggest that you join Associated Content first , look through the notes here, and then start experimenting with the other options. There are a lot of options, but AC is one good place you can start that I can verify payment from.