The Advantages of After Hours and Pre-Market?

[JMoney]

Being a new trader, I have yet to understand the advantages of After Hours and Pre-Market. Could someone tell me the advantages and strategies for this? Also, I know some of you here don't like trading during these periods, so I would like your input on that also.

[stocky]

I donot trade pre-market, rarely at open but AH is very important. Once the original reason to trade the stock is over, its best to get out of stock as soon as possible. Most importantly like bad earning, bad news etc. you can always see that whenever the slide starts even the best exit is start of AH, though its just my conclusion.