What if someone was to come in and buy out all the stocks for yahoo...and be just a normal person? Like say I went and bought all yahoos stocks..what would be the outcome?
The outcome would be that you would own Yahoo. How the company goes would depend on if you were a wise businessperson or not.
Technically it's not really possible. Companies protect their stock, otherwise any competitor could buy you out at any time. To be able to buy all of their stock or at least 50%, there would have to be that much available for sale. Company employees and owners would likely protect their stock and not sell it. If someone were to start buying up a company's stock, they would know about it very soon. They could take measures against letting you get more. They could buy some stock from shareholders at an inflated price. They could also convince their shareholders not to sell. Really it isn't financially viable to take over a company this way. If it were, Microsoft would already own Yahoo.