After these tenants move out, I'm thinking of just keeping the rental empty with furniture. It sounds stupid to give up $4,200 a month, but I really hate dealing with the homeowner association, move-in/move-out rules, and maintenance issues. Given that the condo doesn't have a mortgage and I have to pay taxes on some of the rental income, I'm not giving up that much. The condo can be a place for my sister, parents, or in-laws to crash when they want to stay in SF for longer than a week or two.
Remember the HillTop ad that Coca-Cola did? If not, perhaps the lyrics will spark a memory - "I'd Like to Buy the World a Coke."  Is the song stuck in your head?  This jingle had the whole world singing, and if that weren't enough, it was recently revisited on the Mad Man series that had everyone humming it again.  The song spoke of unity and tolerance, and as consumers, we gravitated to it and shared it.
The U.S. Internal Revenue Service categorizes income into three broad types, active income, passive income, and portfolio income.[1] It defines passive income as only coming from two sources: rental activity or "trade or business activities in which you do not materially participate."[2][3] Other financial and government institutions also recognize it as an income obtained as a result of capital growth or in relation to negative gearing. Passive income is usually taxable.
You can find dividend stocks using Google Finance Stock Screener which is free to use. Set the search criteria for the P/E Ratio, and Dividend yield (shown as a percentage) criteria. You can set minimum and maximum values; in the dividend yield box, set it between 2 and 100. This will search for stocks that pay dividends worth between 2-100% of the current stock price.
stREITwise offers a hybrid investment between traditional REIT fund investing and the new crowdfunding. The fund is like a real estate investment trust in that it holds a collection of properties but more like crowdfunding in its management. The fund has paid a 10% annualized return since inception and is a great way to diversify your real estate exposure.
Buy vending machines and put them into areas that receive high levels of foot traffic. The investment cost is high, but from then on it is a matter of restocking the machines as needed. If you are able to find success with your first machine, there is nothing stopping you replicating it many times over. This business model is very passive, but the high start up cost and low potential for super profits holds it back in my opinion.
Viral marketing or viral advertising is a business strategy that uses existing social networks to promote a product. Its name refers to how consumers spread information about a product with other people in their social networks, much in the same way that a virus spreads from one person to another.[1] It can be delivered by word of mouth or enhanced by the network effects of the Internet and mobile networks.[2]