Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of coin-counter and Redbox DVD renter Coinstar (Nasdaq: CSTR) dropped as much as 27% today after the company updated its fourth-quarter earnings guidance.

So what: Live by the Redbox and die by the Redbox. Or at least that's what Coinstar's latest projections seem to show. The company cut its projected earnings range to $0.65 to $0.69 per share from previous guidance of $0.79 to $0.85. Analysts, on average, were looking for $0.84. The company placed much of the blame on the 28-day delay on new titles that the company had agreed to. Interestingly, my fellow Fool Anders Bylund noted that while Netflix (Nasdaq: NFLX) agreed to the same delay, it has actually been a plus for Netflix.

Now what: It's hard not to think that investors are overreacting here. Stepping back to look at the bigger picture, Coinstar noted that at Redbox -- 28-day problems and all -- revenue grew 38% year over year and same-store sales grew 12.5%. Analysts are likely to chop their 2011 earnings forecasts after this fourth-quarter disappointment, but if investor pessimism continues, Coinstar's shares start to look interesting -- even for non-growth-investors like me.

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