NEW YORK, July 28 (Reuters Breakingviews) – The digital advertising hunt is back on. Meta Platforms (META.O) and Alphabet (GOOGL.O), respective owners of Instagram and Google, got their mojo back thanks to renascent marketing activity. With some $130 billion still earmarked for commercials on traditional TV, the pack of vultures scavenging for revenue has grown to include Uber Technologies (UBER.N), Netflix (NFLX.O) and others. Meta and Alphabet this week both unveiled solid upticks in their second-quarter top lines. The company led by Facebook founder Mark Zuckerberg notched a 12% rise in ad sales and expects third-quarter revenue to increase by…