Shares of Crocs (Nasdaq: CROX) plummeted after the company lowered guidance. Can Crocs regain its footing? Blockbuster (NYSE: BBI) made a recent bid for Circuit City (NYSE: CC). Could the new duo be a serious competitor to Apple (Nasdaq: AAPL), Best Buy (Nasdaq: BBY), and Netflix (Nasdaq: NFLX)? And how do you know when it's time to sell? In this installment of "Fool Video," LouAnn DiCosmo looks at that question and talks about some other stories on the Fool radar.

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