Well my first social networking site would be Facebook. This was where I started making many friends online and the reason why I joined it was to search a friend whom I used to like a lot, it took me a week to search but I found my friend, now I have been blocked by thet friend that is another part. But the main fact is Facebook is a very nice platform where you can find lost friend or with those person whom you have lost contact with.
It is a very nice site as many people can share their opinion by sharing, commenting, posting and liking other comments. But the cons of it are that many antisocial elements are using it to spread violence and creat hatred in people. So these things should be stopped by Facebook administrators and create it a cleaner social networking site.