Most people are confused as to what a market is. They see it either as a place one goes to buy stuff (e.g. a mall or bazaar) or as Wall Street. While both certainly are kinds of markets, they are not the only kinds.
Simply put, a market is just the term we use to describe the exchange of goods/services/ideas between two or more people. That’s it. The stock market is a market as people buy and sell shares of companies, but we also have a market when two schoolkids trade baseball cards. In fact, the Internet is full of markets: Craigslist, eBay, Amazon, forums, WordPress, etc etc etc.
Markets allow for the co-ordination of buyers and sellers. In this manner, they allow goods/services/ideas to go to where they are most valued. Therefore, both parties in a market benefit as each one obtains an item s/he values more than what s/he trades away. Thus, wealth is created.
It really is this simple.