Panda is an algorithm that is employed to websites overall and has turned into one of core ranking signs. It measures the grade of a website, which you may read about in their guidelines. Panda enables Google correct ranking and to take quality into consideration.
Sites that publish high-quality content have little to fear by the upgrade, but it might have been hit sooner or later by Panda when your site has participated in practices that are problematic. From a company perspective, of preventing Panda, your very best hope would be to create a web site which becomes a source by dint of its content.