I use to write 3 articles per day. I focused on keywords to help them rank well in Google. However I've stopped writing articles because I started to just repeat myself and found it hard to come up with new things to write about. This led me to buying bundles of articles already written, and now I just buy articles reword them and submit. I try to do about 3 - 5 per day.
What's the earnings/month/article on average (based on traffic)? You write them for seo/traffic or both?