I have read a good definition here:
http://www.isitebuild.com/passive-income.htm
I have established a goal for an increase in my passive income and January was good and February is starting to resemble last month and growing. Since I don't have a "job" so to speak, passive and continual income online is very important to me. I think, for many people, it can be translated into a few hundred, a few thousand to probably over 1 Million dollars a year for marketers who have great programs and successful affiliate set ups. I know of some affiliate programs generating in excess of 1 Million dollars per month for some people. But they are in industries I have no interest in whatsoever.
You all know eBay has produced many millionaires in this profit range. Adsense can generate a very large income if you have the traffic. Many sites boast 1M-10M visits per month so you can imagine what kind of income 1M visitors, with a 10-17% CTR could do for your Adsense bottom line.
On the front page of Google's Adsense it says:
Premium AdSense service available if your site receives
5 million+ search queries or 20 million+ content page views a month.
So you can imagine how much money the above would mean to site owners looking for a passive income via Adsense. I'd say it would be more than enough to retire very quickly and leave a lot of money for the children and grandchildren to burn. (:-
Mario