Happy birthday, GOOG. Five years ago today, Google sold shares to the public for the first time in what was one of Silicon Valley’s most discussed, dissected and debated initial public offerings of stock. Its debut on the Nasdaq market on Aug. 19, 2004, came after numerous twists and turns, including a Playboy magazine interview with the company’s founders that drew the attention of the Securities and Exchange Commission — apparently they read it for the articles — and a last-minute drop in the initial offer price.