Hi @crypto.piotr,
The proof comes from this post which has a value of around 14$ now. This is a screen capture of the source code of this article:
The smartsteem link in this post has now a rel="noopener" but it is a "do follow" link. So it is relevant for search engines.
Thank you very much for your help with this post. The engagement was truely amazing. I wouldn't have imagined that there would be so many comments :-).
Best regards,
Achim