“NUD is the international day when all Facebook users shall protect the sacred nature of friendship by cutting out any ‘friend fat’ on their pages occupied by people who are not truly their friends,” according to the show’s website.Meanwhile, the latest new social network's key feature is that you only get 50 friends, who are meant to be your closest friends and family.
While there is something to be said for periodically deleting non-relationships from social sites (i.e., anybody whom you can't remember who they are), the premise of both of these—that social software friend lists should be only for people we consider to be actual friends in real life—goes against the use cases of social software site; one of the things that makes sites like Facebook useful is because they're good at managing weak links; of keeping up with people whom one isn't sufficiently close to to individually spend time with. There is probably less call for a site that is limited to one's 50 nearest and dearest (not to mention the drama it may engender, akin to MySpace's "Top 8" ("You added him but not me; what am I: chopped liver?")) than for one for keeping up with various spheres of acquaintances, buddies, contacts and other weak links, and compartmentalising one's public identity and profile between them appropriately.
Yeah, Path's 50 friend limit seems like an odd idea. Apart from your objection (that maintenance of weak ties is what we actually want from social software), the thing that bothers me is that the restriction is arbitrary (despite the claim to be based on Dunbar) and most successful technologies succeed because they are flexible and allow the use made of them to evolve. People find uses that the designer didn't envisage. This happened with Facebook - it's not the browsable college-student catalogue it started out as.
Furthermore, for most Facebook users, the "friend" relationship modeled in the software doesn't really mean "friend", but something more like "someone I have interests in common with" - thus a friends-list acts as a relevance filter on incoming news as much as anything.
On the other hand, if the movie is to be believed, a significant attractor to the initial version of FB was its exclusivity. The 50 limit forces people to be exclusive and may attract people who like that.