
Stocks were there first. It's the oldest trading instrument. Initialy the stocks were used by Dutch merchants who had wanted to build their own ships but couldn't afford it. So they borrowed from different people and issued official papers in exchange that guaranteed the lown returned with interest, or in short - dividends on investment.
As time went by these first stocj ventures were closed but later on they were renvented in more or less modern form. The stock market, therefore allows companies to raise capital for expansion, liquidity, or R&D, etc.
Now the stock market is considered to be more stable and solid that the forex market, for example. It's true that stock prices tend to fluctuate widely, but not as widely as the foreign exchange, especially now. So many investors prefer to have more solid investments than higher profits of more volatile market.
However, even solid investments can go down the drain if they are placed with unreliable broker. There's a hot debate on the web as to whether avafx scam or not. I can personally testify that it's not - i dealt with them for a couple of years and except some minor glitches everything was alright. May be some former clients, those who opened accounts and waited for dollars to start pouring without learning the market, got burnt and decided to smear them, but from my personal experience they're cool.