Head to Supermario.com - you might be surprised with what you find. Instead of anything remotely official, Supermario.com is populated with hordes of rip off flash games featuring Mario. Now Nintendo are looking to put a stop to this, acquiring the Supermario.com domain in the process.
It seems strange that Nintendo are only now attempting to shut the site down and acquire the domain, considering the content on the site has apparently remained unchanged for the last year at least. It could be something to do with the fact that Nintendo are currently working on Super Mario 3D Land for release later this year.
According to Domain Name Wire, Nintendo has filed a complaint with the World Intellectual Property Forum in order to take possession of the domain, and considering what the website is being used for, most likely they'll be successful.
Nintendo 1-Ups for Popular SuperMario.com Web Site [Domain Name Wire]