You can see a demo of the product working when you click on the link. A welcome message will show up at the top welcoming all Hacker News readers.
Also the pricing table at the bottom is 100% dynamic. We actually have three pricing tables: one for HN readers, one for Product Hunt readers and another one for everyone else.
Questions or comments, just let me know.
We already have the Javascript plugin. You just install it on your site and through the admin interface you can then start configuring what content to show based on the referral url.
Does it makes sense now?