Props to you for trying to open up people's minds! My first introduction to polyamory was also through "The Moon Is a Harsh Mistress," and later another of Heinlein's novels, "Stranger in a Strange Land."
I haven't addressed things like censure by society yet. For instance, the fact that Tiger Woods would probably have lost his contracts even if his wife did give permission. A married person having sex with multiple people, with permission or not, isn't considered "wholesome".
We have a long way to go until acceptance. During all the Oscar coverage, Mo'nique freely discussed her open marriage and took a lot of criticism for it, and even downright ridicule from interviewers, TV show hosts, etc. But, the more visibility we get from people trying to get the word out, it will slowly become more accepted.
I'd echo others' cautions: The more I've learned about polyamory, the more I've seen that there isn't one "right" way to do it. There may be a "right" way for you, but that might not work for me. And many people are happy and fulfilled in monogamous situations.
I assume from reading your blog that your intended audience is mostly monogamous? In that case, you might consider not arguing against
monogamy so strongly right away, since that is likely to turn off readers to the whole concept. Maybe you might have more success offering it as more of an "alternative" choice? (At least until you get them hooked on the idea.) Just my two cents. Take it or leave it.