"But we already knew that, didn't we," she says, smiling.
Never mind it's a great time-waster: you can be entertained AND keep up with your friends, all without turning your brain on.
But now a study and a report from a professor at the University of Portsmouth, has confirmed it. (This is noteworthy, because earlier studies have reported that looking at Facebook could be bad for your mental health.)
According to Dr Alice Good, Facebook can make you feel better if you're down, particularly by allowing you to look at old photos of yourself, and seeing your old wall posts.
According to Psychologist Dr Clare Wilson, of the University of Portsmouth: "Although this is a pilot study, these findings are fascinating. Facebook is marketed as a means of communicating with others. Yet this research shows we are more likely to use it to connect with our past selves, perhaps when our present selves need reassuring.
“The pictures we often post are reminders of a positive past event. When in the grips of a negative mood, it is too easy to forget how good we often feel. Our positive posts can remind us of this."
It can also be helpful for older people suffering from memory loss, depression or anxiety, by allowing them to self-sooth, and be reminded by the things that matter to them.
Of the 144 who participated in the study, the average age was 34, and 39% of the sample had experience mental health problems. Eighty percent had a smart phone, and 86% visit Facebook more than once a day.
So there you have it: a prescription to peruse.