Investors in GoPro 's ( GPRO 1.54% ) IPO are a pretty ecstatic bunch -- and for good reason, as the company's stock is up nearly 75% from its public debut.. Shares of the action video photography company rocked the Nasdaq with the adrenaline-fueled rage of one of its users' signature videos. But after the company and early investors benefited from a $3 billion valuation, we as investors have one question: why the enthusiasm?