CHARLOTTE, N.C. ( Stockpickr) -- On Aug. 13, the share price of Apple ( AAPL) had been hammering relentlessly for two hours at the immovable $475 resistance level when, at 2:21 p.m., Carl Icahn tweeted: "We currently have a large position in APPLE. We believe the company to be extremely undervalued. Spoke to Tim Cook today. More to come."What happened next -- the instantaneous result of this tweet -- is very dramatically represented in the chart below and is being referred to by many as the "Icahn Effect." People like to point at the past year's amazing run-up of Netflix's ( NFLX) stock price as a prime example of this so-called Icahn Effect. One of the most common questions people are now asking me is: Will Apple's stock price soar the way Netflix ran up after Icahn announced a similar large investment last year?