When we buy stocks, we are actually buying into those businesses. So when you own the shares of example company A, you are actually buying into a small portion of company A's business. That is stocks in a nutshell. Of course you would want to make sure that company A is doing very well with your money running its businesses and wish it has the potential to grow stronger - such that it's earning will increase and demands for its stock will go up, in turn leading to increase in its share price. Stock market is a weighing machine in the long run. Here are some very useful notes sourced from http://wiki.masterlifefaster.com/Home/investing which is modified from Buffettology: How to identify a great business

1. Does the business have brand-name products or services that give it a monopoly in the market?
2. Does the business have a multi-year track ...

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