Yahoo continued to signal its decline Wednesday with an announcement that it will lay off 2,000 employees, its sixth mass firing in four years. The company has struggled to compete with Google, Facebook, and other upstart companies that cut deeply into Yahoo’s market, and has shuffled through three CEOs in the past four years. Yahoo says the cuts will save $375 million per year, and are part of a strategy to rejuvenate the company. Fired employees will be notified Wednesday; the company would not say whether they would receive severance benefits.