According to the article, this "free" service comes at the cost of their readers privacy, not being in control of your whole blog (comments) and increased loading time because of the size/requests needed.
If the book is documentation, I only read as needed.
> Do you read it in one go and later try examples or go through entire book by trying all examples?
I do a few of the examples until I learn and figure out how the <topic> works. I won't be doing all the examples, if they're just teaching the syntax or simply showing stuff that can be found at the documentation like functions parameters.
> Do you read the entire book or just the part to get the job done?
I only read the whole book if I'm completely naive and want to deeply learn about the <topic>. I usually jumps chapters which have content I've used before and is not difficult to me.
> What methods/techniques have you found useful while reading such books?
Write your own cheatsheet or take notes as you go. Also use the official documentation for functions definitions and similar stuff.
This is fine for most people; the "interaction" nowadays (likes, retweets, ...) doesn't really represent support but a lack of communication skill from the consumer.
When someone likes something without anything to say it's just a metric, doesn't bring value to a discussion.