Facebook is a very well known social media app that really ages from 10 or 11+ have. Facebook has a certain age limit so if you were older than 18 you could have one. It's the 21st century and kids are intelligent when it comes to electronics. So don't be surprised when you're 11 year old has Facebook because to kids being safe using it doesn't matter being apart of the crowd is more important. Facebook is one way that friends can stay in touch and communicate with one another. You can post statuses and look on other peoples timeline what they write or what other people write on it. Facebook isn't dangerous to use the person on the other side of the screen is choosing to make it unsafe or dangerous.
Instagram is also a popular social media. Instagram is nothing like Facebook because Facebook is friend requests, sharing posts, writing statuses, & messaging. Instagram is posting photos & commenting. People can also request to follow you. You can also choose to be private where people you follow or request can see your pictures. That's some of the beauty of Instagram is that YOU choose who can and cannot see your pictures so Instagram is a little safer than Facebook. You can also DM people. When you DM someone it's the same thing as messaging.
Twitter is a very common site. It's used a lot more than anything else. I personally don't have a Twitter because my cousin say that Twitter is more dangerous and it's just an awful site. Twitter is posting, reposting, & following people. Kinda the same thing as Instagram. I honestly don't understand why it's better but I guess it's better although I don't recommend it.
Snapchat is the ghost app that a lot of people have. Snapchat is taking pictures putting them on your story, friending people, seeing other peoples pictures, you can also record, and message people. The limit to how long someone can see your pictures is 10 seconds long. If you want to record a video the video can only be 10 seconds long no longer. Snapchat is fun and easy to use. There's really no danger in using it unless you accept people that you don't know and message you nasty things. Other than that personally Snapchat is better and I use it more than anything else.