Most companies actually conduct their own Social Media Background Checks these days, although in an informal and below-the-radar fashion. Recruiters or HR staff usually google or fb the names of various employment candidates, and, as Henry Kissinger once said, “we go where the investigation leads us.”
The problem is that these searches are conducted at different times in the recruiting process, and at different depths. That is, certain folks get researched a lot more than others. These inconsistencies can lead to charges of discrimination and legal problems, not to mention invalid conclusions, so be careful!