Originally Posted by UniqueIdeaMan
If I run the script on my site then I see cURL fetches the page (the above link) but I see no response on the comment form.
You do know that 99.999999999% of all WordPress websites either run Akismet (look it up) or do manual comment approvals. Automatic things like you're trying to do trip so many SPAM filters it's not funny. It's been done and tried before a lot more succesfully. I won't mention the product sname because it's only reason for existance is black-hate SEO, but rest assured that auto-posting comments has been around, done, and solved for years now.