"However, it isn’t difficult to get around 100 visits per day to a blog, now is it? Seriously, a good rule of thumb to live by is understanding that 100 visits to your blog should make you about $1 dollar. If you can maintain that level then you can soon retire and quit your day job."
(SNIP)
"A few months ago, my goal was to make $1 dollar per day per blog. Today, some of these blogs have grown to make over $4 dollars per day. One blog makes about $40 dollars per day. Another blog makes almost $100 dollars per day. Other blogs (not shown) are starting to reach the $1 dollar per day mark.
The above screen shot doesn’t even show HALF of the blogs reported in my daily Adsense report. It only shows 15 blogs. I have another 85 or so on the list that make between five cents to $3 dollars. All in all I make anywhere between $150 dollars per day to $350 dollars per day across the board. And that is with Google Adsense alone." Read the complete post.
Admittedly, building 50 to 100 websites with high quality content is not an overnight job. My experience is that working three to four hours a day I can set up a site with several pages of good content in about a week or ten days, depending how long I go without checking my bloglines account.
Gary Conn's approach is a long-term method, probably a year to get 50 sites up and running for most people. Even using free article sites it still takes time to gather content. While there is good content available, there is also a lot of bad, so the editing process takes time.