As a member of our 10% Promise team, I see all kinds of wild stock moves. Every move has its own story, and some of them teach me something I didn't know about the market. Here is what I learned this week.

To Zagg or not to Zagg? That is the question
Apparently, Apple (Nasdaq: AAPL) has an impact that goes far beyond the tech business. Shares of accessory company Zagg (Nasdaq: ZAGG) went for a wild iPad inspired ride this week when Apple announced the iPad 2 and its Smart Cover. Investors thought Zagg had met its match, and the stock dropped 24% Wednesday after the event. But cooler heads prevailed on Thursday, when the stock popped 20%.

At Zagg headquarters, I'm sure the initial reaction to Apple's Smart Cover was, "Why didn't we think of that?" But to look down and see your stock was also down 24% was just salt in the wound. The Smart Cover may not be good for the ZAGGmate, but Zagg's other products should be in good shape as the iPad 2 rolls out.

I just wish I had jumped on it when the market panicked, but I was too busy focusing on the shiny new tablet everyone was talking about. The lesson here: Keeping an eye on big prizes like the iPad 2 is good, but watching for reactions elsewhere in the stock market may lead to even better ways to profit.

Short vs. Long: Round 13
The fight over China MediaExpress (Nasdaq: CCME) continued this week with the 13th time this stock has hit our 10% Promise list. This week, the shorts won big when the stock bottomed at $10.68 on an intraday basis, but it has already climbed back above $13.46 as I write.

The battle over the legitimacy of the company has left many an investor confused, as analysts back the company and investors continue to short it. We give Wall Street analysts a lot of grief at the Motley Fool but they've either got this spot-on or have had the wool pulled over their eyes. I'm just wondering how many rounds this fight will go?

Avoiding bankruptcy isn't always good for shareholders
Isn't avoiding bankruptcy a good thing? YRC Worldwide (Nasdaq: YRCW) was hit hard this week after announcing a restructuring that moved the company away from bankruptcy but would dilute shareholders badly. I would have expected a move in the other direction, but even without final details management saying the dreaded words "very substantial dilution" was enough to send this stock for a ride downward.

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More Interesting Moves This Week: