I've been in IM since 2005. I built up a huge list of 60,000+ satisfied subscribers in 2005-7.
I paid the mortgage, the private school tuition for our 3 kids, and much more with the money I earned from that list.
But... I started to realize that I was pretty much tied to my list, and if I stopped working for a few weeks, my income would go down. I wanted something passive, where the money would come in month after month even if I took a couple of weeks off of work....