I personally have met Craig Newmark and respect his frugal style. He insists on providing free of charge lists for internet posting of buy and sell. That includes sale, rent of real properties.
This is a must for those who do not know how to navigate in and out of the system.
It gives you insightful rules what stands out and what do not.
As a realtor I was able to find business and learn to find out listings became properties for rent posted by other people. Majority are coming from overseas. However, if CN charges a nominal fee, the free rampart posting will go away.
This book does not teach me much as I know many of them. The blogging site is a forerunner of social media. I suppose one can become addict to it. I use SF Bay area version and the posting are more liberal.
All in all I gave *** on this book downloaded for a fee.