tight stop losses being triggered, page-8

Most trading platforms let you put in automatic buy and sell points if you wish (as with anything it cost you a fee) If the stock hits a certain pre determined price this will trigger a sell order (in the case of a stop) which will usually be priced at just below the trigger value.
It is a way of limiting your loses , it may mean you miss out on some profit if the price bounce back up quickly but its all about managing the level of risk , working out what you are prepared to lose if things don't work out the way you expect and want.
Not something investors usually do as long term most the ride out the highs and lows.