Quote from Rearden Metal:
More memories of the Golden Age:
<img src=http://bigcharts.marketwatch.com/charts/big.chart?symb=amzn&compidx=aaaaa%3A0&ma=0&maval=9&uf=0&lf=1&lf2=0&lf3=0&type=2&size=2&state=8&sid=41519&style=320&time=13&freq=2&nosettings=1&rand=5994&mocktick=1&rand=6286>
<img src=http://bigcharts.marketwatch.com/charts/big.chart?symb=yhoo&compidx=aaaaa%3A0&ma=0&maval=9&uf=0&lf=1&lf2=0&lf3=0&type=2&size=2&state=8&sid=16665&style=320&time=13&freq=2&nosettings=1&rand=5325&mocktick=1&rand=1301>
<img src=http://bigcharts.marketwatch.com/charts/big.chart?symb=qcom&compidx=aaaaa%3A0&ma=0&maval=9&uf=0&lf=1&lf2=0&lf3=0&type=2&size=2&state=8&sid=8267&style=320&time=13&freq=2&nosettings=1&rand=5025&mocktick=1&rand=9630>
Come to think of it, you don't even need to go back to the Golden Age to find such examples:
<img src=http://bigcharts.marketwatch.com/charts/big.chart?symb=tasr&compidx=aaaaa%3A0&ma=0&maval=9&uf=0&lf=1&lf2=0&lf3=0&type=2&size=2&state=8&sid=661485&style=320&time=13&freq=2&nosettings=1&rand=652&mocktick=1&rand=1349>
Your cmgi example is correct. None of these stocks have risen 2000% in 18 months.