I agree with the research findings, but my reasoning for depression is a bit different. The primary reason is that Social networking sites have a certain amount of visual medium associated with it, by way of allowing the members to post photographs, etc... Now when you see your close friend from school posing for pictures at exotic locales abroad and you're in a point and time in life where going abroad is just a dream, unconciously it creates depression with you. This is just an example, but there could be more reasons for depression along the same lines.
Primarily because in social networking as the author has mentioned, there is waiting period for replies. if that reply is late even by a few seconds anxiety increases in the recipient's heart. Also pondering the same issue with people induces frustration and later on depression. Again social networkers tend to meet the same people everyday in these sites which in itself is boring which develops into depression
yes really sometimes...I tend to feel anxious about the replies... but it is not traumatic...and it is not even for an extended period of time...just for alil while...