That said, lot’s of people are making extra money by publishing their own books on Amazon. For instance, my friend Bob published a few books on Amazon on how to make money blogging and has done very well. The first book provided basic tips for a small price, but his next book, Pro-Blogging Secrets, is offered at a premium price and he also has an online course.
Cashcrate.com is an excellent way to make money. You complete offers and take surveys and get payed for it. I read an article on it from a guy that has doing it for sometime now and he explained it as voluntarily signing up for spam and gave a whole layout of the best way to do it. and you can actually make decent money. Pretty much make a separate email for spam.
Ebooks can be a hard path to online success too, from my personal experience but as you rightly said, it can be a great gateway vehicle to drive traffic to other monetized sites. Having said that though, getting your ebook on Amazon, Barnes & Noble, Lulu, Smaswords etc., is a great way to get noticed and make money overtime. An arresting e-book cover is a MUST! And if you are a DIY freak like me, you could do your own e-book cover for $0. I also use a graphic design software similar to Philip’s.
However, like anything else truly worthwhile, apps require a significant investment of your time or money upfront. If you don't have the skills, then you have to hire someone who can assist you in creating a great app. But first you need to come up with an idea that will sell. Do the proper market research and analytics to come up with the right app.
I have a personal blog that I use for journaling. I became good enough that I opened my own business as a social media consultant. I’m now making a decent amount of extra money. I am also a photographer with a lot of graphics program experience, so I make a little more by doing graphic design, photography, and even digital enhancement. You don’t have to be the best at something in order for it to be profitable; you just have to put in the work and be better or cheaper than other people out there. However, it IS work.
…Marketing an eBook is definitely the hardest part. Ebooks have exploded in popularity and the market is unfortunately saturated with crap from people who thought they could write a quick eBook, put it on an affiliate network, and make millions. However, if you CAN find a good way to market (or possibly have others market by having it listed on affiliate networks) then an eBook can be a great way to make some residual income.