For four decades, South by Southwest has been the place where pop culture gets made. Where an unknown band becomes a household name, where a scrappy indie film sets off an awards-season avalanche, where a tech idea finds its first true audience. This year, as the festival marks its 40th anniversary, Newsweek will be on the ground in Austin, Texas, to cover every moment of it. “We started in 1987 as an independent music conference and festival for about 700 people, and it has grown into this