Many people feel uncomfortable using Facebook in a professional context, and it’s OK if you’re one of them. However, with many businesses creating their own pages on the site, it’s worth at least investigating whether the company has any information that you can use when sending them your resume.
While Facebook is generally used for socializing with friends and family members, it can also be used appropriately to research a potential company. The article linked above gives jobseekers tips on discovering the “corporate culture” and giving your name recognition to potential hiring managers that may also be administering the Facebook page. Sometimes companies list corporate events on their page, so make sure to like them and maybe even show up at an event. This way, you’ll get valuable face-to-face time with people you could potentially work for.