This was a great article by Robbie, and I have to say, I agree pretty much on everything. But if you take the recent Google updates into account, and how difficult SEO has become over the last 12 months, maybe part time might not be the way to go. Unless you are OK making a small amount of money every month for your efforts.
On the other hand, maybe your full time job allows you to outsource a number of your activities, especially when it comes to link-building, and you don’t really mind.
I think being a part time affiliate is good enough just as long as you have a good website that generates a lot of traffic, that will eventually convert and bring that additional income at the end of each month.