140 Characters, or 6sec Video, Chatting via Pics or to People in you interests, there is something common in all this, which is restrictions, and that is the only reasons, they are famous!
The only reason, these platforms, like Vine, Twitter, Instagram, Snapchat got so viral and famous, is because they never allowed you to do everything. They bounded you to with certain limitations. They showed you the real amazingness of restrictions.
Let me dissect it and explain it to you, on why Restriction is such an important aspect to drive the growth of your app/product.
By restricting them, you actually open up their minds to convey anything they want in a way you want. It might sound like Dictating your way to people, but hey, Future is created this way only.
How will people know what they want, unless they see it! – Steve Jobs
Consider the 1st case of Twitter
The time it started EXPERTS PREDICTED that twitter will never last, or its a bullshit concept. Nothing can be expressed over 140 characters. They failed, they had too.
But the best thing that most missed was, its realtimeness. Imagine it like a cocktail party with everyone around is expressing themselves on air, and you have a shot to jump in and build communities.