There are so many church goers connected to these mediums, and I daresay, many of these people choose to post great theological, spiritual and Godly comments on their profiles.
Now, I'm not trying to knock these gestures down... they are very true and encouraging comments. Some people I know utilize this media to do great pre-evangelism to their friends and also encourage their brothers and sisters in Christ immensely. But sometimes, I find that some of these comments become a mere facade for the person posting. Because I know how some of those people actually go about living their lives, there can be sometimes a big discrepancy between the comment and the person. This person who is posting some encouraging verse, the next day, he/she is gossipping, not paying attention during sermons, being rude to other people, etc. etc. A person's social media status does not determine how they are living. In fact, when non-believers see this contrast of lifestyle and commenting, it can even dissuade people from Christianity! How a person lives their lives is by far more important than a mere comment or profile message.
We as Christians need to live out authentic lives that are the example of Christ in us. Let your transformed life do the talking. Don't fall into the trap of smokescreening your life by your social media profile. Live for the Glory of God only.