I don't think the Facebook issue has anything to do with their brand. I think the attitude that Facebook is addicting actually has more to do with people becoming bored with the service and noticing how much time they actually spend on it.
Edit:
>> "... my friends and I used Myspace in middle school, and we too abandoned it (for Facebook) once we reached high school"
The conclusion drawn here might be incorrect. I'm not sure of the age of the author but could it be that he reached high school at the time when Myspace had fallen out of favour with most people and everyone was beginning to transition to Facebook?
It's an interesting post, particularly the part about Snapchat. His sister's use of it seems to fit with the way Facebook was advertising Poke (I thought they just had to find another angle besides sexting but it sounds like there are other uses for it). After hearing this description it sounds like something I might use. A lot of the photos I share on Twitter/Instagram and things I find interesting or funny but I never need to see again. I usually have to then go and delete them from my camera roll and occasionally I go back through my Instagram feed and delete them. The idea of Snapchat (expiring images) seems to be what I need.