I have found people live on Facebook. To be fair I am an older person.

These Popular Social Media Sites are,
1 – Facebook. This is easily the largest social networking site in the world and one of the most widely used.
2 – WhatsApp.
4 – WeChat.
5 – QZone.
6 – Tumblr.
7 – Instagram.
8 – Twitter.
9 – Google+

The most important YouTube SEO tips,
1.Title Of The Video – Use Keywords.
2.Description Of The Video.
3.Naming Your Video File.
4.Optimizing existing videos using search data.
5.Use The Closed Caption (CC) Feature In Your Video On YouTube.

Step 0: Figure Out If You're Already Famous. Give yourself a long, hard look in the mirror and be honest — are you already famous? ...
Step 1: Pick Your Platform. ...
Step 2: Choose A Theme. ...
Step 3: Show Up Consistently. ...
Step 4: Post Quality Content. ...
Step 5: Get Social IRL. ...
Step 6: Repeat.

Fb + Insta + Twitter + LinkedIn + Rediff & Last one Tumblr

tik tok is very fast

facebook is the best tool for me to advertise and get leads. Google+ is gone, twitter cannot say much about coming work from it

Don't focus on only one social media platform, try the following platform as they are very good.

Facebook
Twitter
Instagram
Pinterest

Facebook, Pinterest, Twitter, and Pinterest are the best social media sites

now a days Facebook and Instagram is the most popular for quick response