Ebooks vs Physical Books:
Physical books have higher production costs, more middle men, and uber thin margins when compared to ebooks and downloadable software products. If you sell 1 to 2 % as many ebooks as you would physical books you can still make about the same amount of profit from it.
Getting on Amazon:
As stated by John T Reed, listing your book on other sites turns your unique market position into becoming another vendor of a commodity that people can get from many locations.
While some people consider books to have no credibility unless they are on Amazon, sometimes your book can get a reference even if you don't sell your book there. This list has had over 1,000 views, and a reader of my ebook told me they just bought my book from that list. I clicked the link to say I found the list helpful, as it helped me :)
Some authors also work their way up in Amazon by reviewing related books or make lists including their own books. There are so many reviewers that there are guides to becoming a top reviewer.
When Pay Per Click is Broke: Competing on Negative Margins:
Andrew Goodman talks about struggling writing AdWords ads for his new cheap book about Google AdWords:
As a result I can get very little search traffic on this term, so the paid search traffic for that book is mostly coming from the content targeting program, which I suspect isn't converting. We are talking about $1.20+ per click to generate content clicks; this is unlikely to pan out.
Yet ironically there are many ads for ebooks costing more (including mine), as well as services and other companies that work in the Google ecosystem, running on the same keywords, doing quite well. But advertising an inexpensive new book on the subject seems to run up against both editorial and quality score issues.
A long time ago I worked for a niche DVD selling company that did not have great consumer lock in and had a $75 cost per conversion using AdWords. I got their cost per conversion down to a few dollars, but sales dropped off sharply too, and their margins were razor thin.
Had they had a larger ad budget (or had they decided to throw a few thousand at SEO before dumping 5 figures into a functionally broken PPC campaign) I would have built them a ton of links and over time they would have ranked across thousands of titles making a bunch of sales from the free search results.
When Search is Broke: Nobody Cares:
Another customer wanted me to market an uber niche product in Australia. They wanted me to set up an AdWords campaign to help with that. I set up their Australia AdWords account, making it a bit broad to see what results they would get, and - as I suspected - they got nothing.
Recently that product started doing well in Japan, and when I asked them why and how they explained how hard they worked to market it offline and how hard they worked to contact related sites. Those social relationships led to word of mouth marketing, which later drove search volumes.
When Search is Broken: Overshaddowed Position:
I consulted a person who sold information about an open sourced project. There is so much link popularity in some of those fields that it is hard to break into the market selling an information product unless you can get some of the most well known people to help give you exposure.
Another common problem with overshaddowning is when words have multiple meanings and tons of people search for the other meaning. This can make it a bit hard to filter out the bad PPC leads, and if you show up when you are not relevant that hurts your overall CTR, which can drive up your click costs.
The Most Valuable Lead:
The most valuable lead is going to be a person looking specifically for you or your product by name.
Many businesses that work well offline are nearly impossible to make functional online using the largest ad networks. You can try to grab related traffic and traffic on peripherally related terms, but until people care or know about you or your product it is much harder to compete on margins.
When you run into the problem of advertising being unaffordable you can always dip a toe into the rich consumer feedback your marketplace offers to learn about the market and build social relations at the same time.
Also the more you can throw your name into what you do or offer the more that can help make up for a lack of ad budget.
How to Get Those Most Valuable Leads:
For people to want to search for you they have to have some type of initial exposure. Testimonials work great, but odds are most people are going to run into ads or affiliate marketing prior to seeing too many honest recommendations.
There are a ton of people who will blog on a wide variety of topics to earn a few bucks. It is not hard to do. When they blog about your topic ideally the profit margins are high enough that people see ads like this at the top of their site.
Some people find the algorithmic holes and fully automate the content generation process, and like it or not, as Dan Thies states, that content converts:
I learned enough in Econ classes to know that Google (through Adsense) is paying for a lot of the spam I see in search results. I've also learned enough from looking at Adsense reports to know that intercepted search traffic has a higher CTR and payout than ads that appear in real content.
Poor Matt... try as he might, he can't change the fact that his employer is paying for more R&D in how to do link spamming, than they are spending on R&D to stop it. This is Cathedral vs. Bazaar all over again, only this time the Cathedral is footing the bill.
I have been debating getting published, but it is going to require synergistic effects with selling updates or else I would lock myself out of the search marketplace due to poor margins.