Recently, within 24 hours, two new accounts† were created on Super User, both advertising the same company on old questions related to PDF. Given the (deleted) spam posts, I truly doubt their profiles are real. And both profiles link to Facebook profiles which might be real, but might be totally unrelated to these users.
I understand we cannot validate all profiles. And surely this is not limited to Stack Exchange sites and Facebook. Nevertheless: should we take action when we're almost certain that the references are fake? And if yes: then how?