I currently hold a full-time offline job and I am just starting out here on Hubpages and hoping that it will be a good source of second income once I get going with it. I've done a lot of research before getting more involved, though, meaning I have read many articles about Hubpages and how to make an income from it.
Fortitude is a very new writing site, created by someone who founded another writing site, Squidoo. This site has about 180 writers so far and is $23.88 for a full account. This is to prevent spammers and it is easy to earn back that payment in a couple of weeks. You get paid $0.05 for reading reviews, which doesn't take that long. You can get paid anywhere from $10 to $100 if your article gets published on the front page. There is not that much competition right now due to the small amount of users. I've earned $3.10 so far from just reading and rating reviews, which is fun. I think this may be the winner because I'm already making a little bit of income after only a week. I'll be able to earn back the $23.88 once I get a few articles published. Give it a go! :)
There is Helium, but I've heard that some people's account balances drop for no good reason and you only get paid to write for certain sections of it.
Suite 101 is a lot of work if you don't have a lot of time on your hands. I was invited there, but I had a lot going on personally during the initial three month writing period so I took a leave of absence. Their editors are very helpful, though.
Associated Content if you live in the US. I'm from Canada.