Don't forget another big differentiator of FB from a bunch of others at the same time was having a few (accidental? intentional?) very dark psychological patter

Don't forget another big differentiator of FB from a bunch of others at the same time was having a few (accidental? intentional?) very dark psychological patterns. At the time, real names were not commonly used online. That coupled with very real 'stalkability' of how FB was used at universities made it much stickier than others. Embedding a "relationship" function into the same software as your "class schedule" was bizarre - but apparently very effective social manipulation. Having in-class life so closely linked with social-life as well as daily preferences and even vacation pictures really embedded itself into a social nerve in a way any network designed with a more singular goal in mind really would not have.