Some large organisations might still use older browsers, like IE6 browsers for SharePoint 2010.
If you open a SharePoint 2010 page in those browsers, you will get a popup saying that “Your browser will have problems displaying this web page”.
This blog has the answer on how to turn off that warning message:
The masterpage has a specific line which you can delete:
But remember: it is better to upgrade to a newer version of your IE !!