If you read a few posts down you will see how one of my passive income streams(Ehow) was suddenly stopped. This is exactly the reason why it is very important to keep working on new passive incomes and than diversify them various sites.
Ehow was a great passive income while it lasted and the income my articles generated was nice but the lesson you can learn is that passive incomes can stop when a website changes its terms or its compensation plan. You have to plan for these types of changes no matter how unpleasant they are, it just a fact of life that nothing is guaranteed.
Having income streams from different sources like ebooks, videos, books, websites, domain parking, affiliates, articles, surveys, dividends, rental income, etc. will help ease the loss of one passive income. Than you can add new income streams and expand current ones until you hit the passive income your targeting.