Om Malik, a technology journalist and investor whose blog, Gigaom, which he founded in 2001, established him as one of the most important voices in Silicon Valley and helped signal a shift in how the media covered the tech industry, died on Wednesday in Palo Alto, California, He was 59. An announcement on his website, Om.co, said that his death, at a hospital, came “after a long health journey with his heart.” Malik started his blog just as the dot-com bubble burst, leading to a recession that also took down many of the journalism startups that wrote about tech, like…