One of the atheist blogs I follow is Daylight Atheism. For the most part, the articles are very well written and I tend to agree a lot with the maintainer, Adam (a.k.a Ebon Musings). However, he recently wrote about the morality of polyamory
In this case, I disagree with some of his assertions and conclusions. Basically, he heavily ties in polygamy with polyamory. He also is just focused on the morality issue of people deciding to legalize polygamy. He tries to make the case that it is different from gay marriage. Also, polygamy is associated with religious subjugation of women. He does say that the libertarian in him says that it should be ok. However, he thinks that it adds so much complexity that it should not be allowed.
So I left a few comments on it. A few other polyamory people found the article and left some comments as well.