Stella joined Facebook a little while ago, in order to stay in touch better with her mother and her sister (her mother, in her turn, had joined Facebook to stay in touch better with Stella's sister).
And she seems to be quite the Facebook user now! Chatting with friends, uploading photos, playing Zynga social games such as FishVille or FarmVille... quite a difference to my use of the site :)
(On the other hand, she said she was annoyed that she had to answer a CAPTCHA whenever she approved a friend, but she didn't want to verify her mobile phone number. So perhaps she's not quite the power user.)