Sycofacer or faceophant or facesucker
People who consistantly post ass-kissing or overly complimentary comments to another person on facebook, almost exclusively in response to a facebragging status post, so that the other person can get confirmation of how wonderful their life is, etc.
Person A posts a facebrag status update with pictures of their children or what their children did that day, which in turn motivates a multitude of sycofacer or faceophant or facesucker posts of ass-kissing suck up comments to person A. Often done by person A to elicit such responses in the first place, and a form of facebragging.