You can find the website announcing the competition at http://www.wix.com/wix-lp/seo-heroes. They claim that Wix SEO is the best and say that if you beat them, that they'll give you $50,000! This is a fun website with some neat animations.
Wix will create a website on their platform optimized for search term "SEO Hero". Anyone else can create a website on whatever platform they want and if an individual website is the highest ranking for "SEO Hero" in 4 months, they'll pay out $50,000. Seems easy enough. The contest started on November 16th, 2016 and you must register by December 16th, 2016.
You can find the SEO Hero FAQs at http://www.wix.com/wix-lp/seo-heroes/faqs.
You can find the rules at Competition rules. Note: I'm not sure why the numbers don't seem to match up with the sections.
You can find the additional information over on Wix but likely the most important difference is the note that a domain cannot have a domain history prior to its current purchase date. This will make many of the websites out there ineligible to compete.