Just wanted to check, as I saw a "regular" version plugin hosted here and a "Premium" version for sale (35.00) hosted on the author's site. I thought all code related to or that relied on WP was required to be GPL? The cost is not a download or distribution fee, and there's no signup or subscription fee to let you download it. It's out and out "click here to purchase".
Can someone knowledgable person clarify this for me?