Fueled by a lights-out Q3 earnings report, a mysterious, but much-hyped mobile plan and an imminent social networking announcement, shares of Google (NSDQ: GOOG) have cracked $700 today, just three weeks after breaking $600. The company’s stock is now up 48 percent over the last 12 months, much of that due to a 187-point move since August 31st. It’s not unusual to see such wild swings among mid or small-cap upstarts, but Google now sports a market cap of $222.5 billion, making it the fifth largest company in the country, as pointed out by USA Today. Companies recently surpassed include Procter & Gamble and Bank of America. Now only Exxon, GE, Microsoft (NSDQ: MSFT) and AT&T (NYSE: T) are bigger. The stock would need to rise another 50 percent to match Microsoft’s $333 billion, although Microsoft has been on run of its own, climbing 19 percent, just since October 19th.