So while i was working on simple social network based project. I certainly have developed required muscles and technologies in order to build fully functional social network.
Problem would be an idea for new social network. Trying to hop in that train is bit late,you missed a big social network boom from buletin boards to the sn giants like facebook and whole that part of internet revolution starting from early 2005 by more than a full decade.
Certainly while that idea to build a social network right now is great idea for educational purposes,you can learn a lot, and master full stack dev skills,and all required skills to build a fully functional product,all with front end,back end,db architecture and whole app architecture from ground up. But to have a idea that you can make next big thing and take over any major social network is in best case funny. Considering i have seen some 1000 ideas on sites like machine idea and none of them make any sense,yet most claim that early overconfidence and security in their idea.
Most major ideas have already been implemented, there are no social network ideas that have not been tried.
We already have big general purpose network that is not going down any time soon Facebook. For short messages twitter,for images instagram,for temporary stories snapchat, great VOIP implementations(Whatsup,Viber), for video sharing, and ton more of narrow social networks on certain topic. Like dating sites,gaming sites, developer social networks, for artists etc. Also networks with bit different design that have really special place in internet culture like 4chan and reddit.
So to sumarize everything up, its really late to get into social networks today. While i do encourage to do similar project for learning and improving your skills, its really not smart idea to thing in past. Follow new trends what is trending and try to find a solution to current problem and make something useful.