In reply to David.

David, back in 2009 I did a research of about 15 CMS to use for nonprofits. I was volunteering for the local community network, which has offered a proprietary CMS to local nonprofits for free. It was completely outdated and the developer move on to other things. So we are looking at the open-source as well as other CMS. We settled on WordPress for two reasons. It was easy to get started and there is a large community helping out when volunteers weren't around.
We migrated 40 organizations within 2 months to their own WordPress site. The most beautiful thing was to see the techies disappear and the newsletter editors and the membership chairs to come it and take over handling the website content themselves. Once the site is set-up you really can teach people how to make it the best tool in their box for online communication. None of the other CMS have a more generous community to helping user getting ahead, and there is nothing easier than adding content to a WordPress site. I was still the only volunteer managing the program until 2014 when I resigned. Most of the sites are still up and going strong.