Supply and demand and fashion have there cross overs. RIM share price has certainly been influenced by public opinion, depite some good sales/figures at times that counter the drops. Self forfilling prophecy that one.

Facebook being another classic, share price based more upon popularity. New startups all the time get snapped up on initial fashion popularity. Nothing is clear cut, should be but it is not. If some stars suddendly endorse a product does it make the product better, may help sales may not but the share price will rise before those sales based upon expectations. So in many ways popularity be it directly or indirectly effects all share price valuations, markets are so volatile by being so twitch dynamicly fast that it is more a direct factor upon share price than it was in years past.