Henry, I think that with Digg and Reddit you can do it MUCH FASTER. I've made $100 per month on my second month, but that's when I didn't know about Reddit, Fark, Stumbleupon, Digg and others. One day, when I got to be #1 in Reddit and got into Digg's top, I made over $220 in a single day.
Quality content isn't all it takes. You also need to be a good marketer of yourself and your sites.