Then how do you profit from them? Momo? I can't get myself to jump on a stock that has risen 100% or more in the last week.
I like those in trading ranges for 10% wash,rinse, repeat cycles but my largest hits were from holding. Sometimes for 6 months or more. Look for one with low float,been stagnate for a long time and is in a sector that is rolling in with lots of new bashers in otherwise empty boards, like gold pennies last year, dot-coms in the late 90's, oil skimmers during BP's spill, etc...and just wait till they take off one day on speculation or probable contract or just news sometimes or MM's just raising the ask on 'em to stir up the bees.
You're very right though, pennies rarely turn into big companies. Their patents will get copied, convert death spirals to gain control or some better method if they have something good.