I have not. While I am intrigued with the possibility of making online income, it seems to be less passive then how I want to spend my time. Regarding your blog / site, you have done quite well for yourself. However, you have to keep pumping out content or your site would eventually go out of business. That sounds like more of a commitment then I would want. Regarding your book sales, it is probably relatively passive now, but certainly was not when you were writing the book. Now if you love it, great. Just not for me.
Passive income is a great tool for building retirement income faster, paying off debts, and, ultimately, retiring early and comfortably. If you have passive income during your retirement years, you potentially could live as well as you did during your peak earning years. Passive income is money you earn without doing actual labor. Often times, it comes from investments, such as in rental properties, stocks, bonds, annuities, and other investments. https://i0.wp.com/www.manicinvestive.com/wp-content/uploads/2016/06/active-income-vs-passive-income.png?resize

Writing an e-book is very popular among bloggers, as many have noted that “it's just a bunch of blog posts put together!” You will not only have to make an investment of time and energy to create the e-book, but market it correctly. However, if marketed correctly (through blogging affiliates in your niche, for example), you could have residual sales that last a very long time.

I’m looking at accepting a professor job. It’ll be more than a 50% pay cut. But I’ll have the same life you describe – endless summers and an entire month every winter to ski. I’m thinking in the end, eventually, I might even end up wealthier in more ways than one. Happy people tend to be the most successful. I have no desire to diversify. Dividend stocks allude me. CDs seem like a good choice for older people, but I have time on my hands and real estate knowledge, so I’m sticking with what I know, despite the fact that most people will tell me it is foolish and I should diversify.
If you know anything well, a place, how to fix something, how to make something, how to do something, you can write a guide for it. You can sell your guide as an e-book, offer it as a download for a fee on your site or reach out to bloggers with similar content and ask if they will offer it as a paid download on their website (for a price of course).
* I use Personal Capital to track all my finances in one place. It’s much easier to use their free software to follow 28 accounts on one platform than to log into various accounts to check my balances. They’ve also got great tools for x-raying your portfolio for excessive fees, recommending a more optimized asset allocation, and planning for retirement with their Retirement Planner.
You are valuable. Your time, your work, knowledge, experience, and output are all valuable. In fact, your employer (or your customers, if you’re an entrepreneur), probably pay a lot of money to rent these things from you. The problem is, whether you’re a doctor, a lawyer, an artist, an engineer, or even a baker, the value you create is consumed once — then it’s gone. You can only sell a loaf of bread once. You can only sell each open heart surgery to one client. The value trades hands, and now it belongs to the customer — you get paid once.
And while real estate is an excellent option, it does require a significant initial investment, so whether or not this passive income stream is right for you depends on your current financial situation. You might be better off starting with an investment strategy where you can build funds until you have a big enough sum to get involved in real estate.
What I Do: I’ve set up multiple investment accounts outside my main operations bank that deals with working capital e.g checking, paying bills. By transferring my money to a couple brokerage accounts and two other banks as soon as it hits my main bank I no longer have temptation to spend on frivolous things. As a result, I can wake up 10 years later and reap the rewards of compounding. My 401(k) is the best example where constant contributions over 18 years has grown to over $500,000 without any savings pain given it just became a part of life. Real estate is also a fantastic asset class for the long term. It’s fantastic to enjoy your home, pay down your mortgage each month, and end up with a paid off asset that has likely appreciated during your time of ownership. 
If you have a specific and in-depth expertise, like programming, coaching, or consulting, then having a well written sales page on your own website can be rewarding. I do this with my web design, SEO, Social media, and coaching services. If you want to become a highly-paid freelancer, I highly recommend you first build your own online platform so you can share your professional expertise, knowledge, and life story with the world. Here's how to start your first website in less than 24 Hours.
Truebill is an app that helps you save money by identifying recurring subscriptions and other bills and helping you cut costs by negotiating better rates and fees. One of their partnerships is with Acradia Power, which has the potential to save you up to 30% on your electric bill. It searches for better power rates in areas where competition is allowed, and it locks in the better prices for you.
For Tim, that was learning and writing a series of books, which he’s truly passionate about. For me, that’s traveling, learning, and working on startups that are “high risk” or have a long road to generating revenue. For you, maybe it’s spending time with your kids and not having to take overtime when it’s offered to you. In any case, the goal is to spend as little time as possible to cover your basic needs; if you want to spend more time to make more money, that’s always an option — but you want it to be an option, not a necessity.
One aspect you might want to add to your scoring is “inflation protection”. At one end, bonds and CDs generally pay a fixed nominal coupon that doesn’t rise with inflation. Stock dividends and Real estate rents (and underlying property value) tend to. Not reallly sure how P2P lending ranks- though I suppose the timeframes are fairly short (1 year or less?) and therefore the interest you receive takes into account the current risk free rate + a premium for your risk. Now that I think about it, P2P lending probably deserves a lower score in the activity column than bonds too (since you probably need to make new loans more often).
Occupational therapist Sarah Stromsdorfer founded occupational therapy site MyOTSpot.com three years ago as an online educational resources for occupational therapy students and professionals. She worked on it every weekend, and her site now makes enough income for her to work as an occupational therapist part-time. She believes it will be another year before her site makes enough money for a full-time living of about $4,000 per month. In addition to the digital products she also makes money from ads and online book sales.
Creating passive income is the key to retiring, especially retiring early. If you want to retire early with the stock market you will have to save a huge amount of money, because that money has to last so long and retirement calculators depend on you using your investment to fund your life. With passive income you will have income coming in as long as you own the investment, without every eating away at the principle invested. Creating passive income may take more work than investing in the stock market, but I think it is well worth the extra effort!