Constraints gave us Facebook instead of Myspace. Constraints gave us Twitter. Constraints gave us Snapchat.
Social networks have thrived on obvious constraints. When looking for a startup idea, sometimes I try to reimagine a popular tool or service with additional constraints.
I agree and would add that constraints gave us Star Wars: A New Hope instead of Star Wars: The Phantom Menace.
Which is to say that creatively working within hard constraints being a good thing is a universal creative rule, not specific to tech or social networks at all.
I doubt it was constraints that made Facebook become more popular, or any other technical reason. It's too bad MySpace isn't what people use anymore. I'd like having all the customization of my home page on Facebook.
4chan has constraints: There are only 20 pages per board (if I recall correctly) and if a thread does not get new posts and drops from page 20, it's gone forever. Just like the twitter 140 characters limit, 4chan has a history limit.
So 4chan perfectly fits in the parent's list of social network like things based on arbitrary contraints
It's entirely not true that no-contraints gave us 4chan. 4chan is definitely constrained: In manpower and financials. Every time the 4chan people post a clever hack that makes 4chan work with what they have, I'm impressed. The fact that they don't filter the content doesn't mean that there are no constraints to the system. The constraints are just different from facebook and myspace.
Social networks have thrived on obvious constraints. When looking for a startup idea, sometimes I try to reimagine a popular tool or service with additional constraints.