I think you should use Financial Samurai to raise your passive income. You’ve already proven that you writing 3 articles a week is enough to not only sustain the site but grow it. Why not have more guest writers post articles? Since you started with the extra post each week I’m guessing traffic is above your normal growth rate. Leverage that up with more posts and my bet traffic will continue to grow.
Residual income is the amount of net income generated in excess of the minimum rate of return. Residual income concepts have been used in a number of contexts, including as a measurement of internal corporate performance whereby a company's management team evaluates the return generated relative to the company's minimum required return. Alternatively, in personal finance, residual income is the level of income that an individual has after the deduction of all personal debts and expenses have been paid.