This question already has an answer here:
Now if the question is stupid forgive me.
From what i have understood so far( i could be wrong )
- Bitcoin is a digital currency service.
Q : What is difference between
blockchain.info and thousand other sites who give me a unique bitcoin address upon registration ? Also are those
bitcoin address unique globally or per site ?
- You can earn money by bitcoin mining ( letting a software solve some complex mathematical problems in your computer)
Q : why do we need to solve a problem ? cant it have like a database which checks id/password combination like paypal and others on a server ?