If I want to compare Instagram with the rest of social media on a scale of one to ten, Instagram will score ten while twitter is 9 and the others will score four. Why? Because of its simplicity and effectiveness. It allows 1000 words to be said silently and through a photo.
Also promotion of the photo is simple, all you need is to tag it with the words. Of course I don’t know who created the hash tag concept, but it’s genius as one can find millions of things just by the simple use of a hash tag. 
So in fact I almost stopped using facebook as it became too crowded for my liking, also I almost stopped using linkedin as its very intrusive, so the only two social media forums that I use are twitter (only if what I want to say cannot be depicted by a photo), and Instagram. 
I also use Instagram to promote my company, and it’s working.  I feel people on facebook are just there because they want to see your news and stalk you, in Instagram you are giving your news and your interests in a photo so the curiosity of the people that follow you is almost instantly killed, and what you put there satisfies them, and they will move to another photo instead and so on.  In facebook one has to sift through screens after screens of data and information in order to find what he or she want to see. 
LinkedIn has become a pain in the neck as all I receive is job requests, requests to purchase someone’s products and services and other requests for collaborations.  It has become a very pushy space for hard sale.  I don’t like that at all. I think sales of ones products and services should not be pushed to the clients, one should first know the clients and know their needs and then suggest if they want to use his or her product or service.  I am getting umpteen number of emails from LinkedIn on a daily basis which is sometimes stopping me from doing my job in helping my students and finding the best place for them to be in. I personally prefer soft sale because it is only disclosed on needs basis. That is why I hate those unsolicited phone messages and emails that try to lure you to buying a product or a service without thinking if I really need that product or service.
So until another genius thing comes to life I will be sticking to these two social media products instagram and twitter. 
Kevin Systrom and Mike Krieger are very clever as they didn’t only create this Magnificent media in isolation, they gave us ways to link our news (pictures) to other social media which is great as now we can really just use Instagram to do our work and spread our news and with few presses on the share buttons we have all our accounts populated with what we want to say.  Incredible really.
Jack Dorsey who created twitter is another genius who taught us how to be very subtle in what we have to say. If you don’t know how to use twitter then I must explain it. You have to write only 140 characters, which is not a lot of course when you think of how much we the human beings love to talk, so we (tweeps) became concise and had shortened our descriptions to fit the required characters.  So twitter had made us rule abiding bunch of course so I wish the governments find a similar way to make us rule abiding people! Of course some times some hooligans use the 140 characters to say bad words, swear, show some muscles and make everybody upset, don’t forget that twitter accounts are hacked and a virus is sent to the tweeps if they open it the computer will blow up.  
My feeling: we the human beings are very social, even our products and services are mostly sold due to word of mouth. So these social media are trying to depict what happens in real life.  Sometimes this succeeds but sometimes it doesn’t.  To me LinkedIn didn’t succeed.