Understanding blockchain and steemit

Hi my name is Ashish prajapati and I am a student.

I have some questions about block chain how I can explain someone who do not have technical skills if you know the answers please comment.

1. How would I describe block chain to someone with no technical background?

2. What are other block chain use cases?

3. Why steemit is different from other social media networks?

1. Any other alternatives of blockchain?