Stocks, etc.

[its me]

I am relatively new here, however I have not seen an Eshkol discussing this topic. And the topic is the stock market.
First the most burning question: why people buy stock? And the types of stock there is. Please comment on this.
There are two types of benefits of owning stock:
1) As a commodity, like gold or gas, etc. their prices tend to fluctuate so everyone who buys stock is hoping to get in on it at a point when it can still appreciate whether in the short term or long term.
2) For the dividends. (see later)
Types of stock:
1) Common stock, the most common type of stock and usually the cheaper version. One of the properties of common stock is, that a company is not required by law to distribute dividends to its shareholders, it is totally up to the discretion of the board.
2) Preferred stock, (cannot be offered by an S Corp). One of the main upsides of preferred stock is, that a company cannot distribute dividends to shareholders without the preferred shareholders being given dividends first. However, they do not have voting power.
There is much more to discuss. I first want to gauge the interest of our fellow coffee drinkers.