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What: Shares of Synchronoss Technologies (Nasdaq: SNCR) have gotten crushed today by as much as 27% after the company reported earnings along with concerns about its business with AT&T (NYSE: T).

So what: Adjusted revenue added up to $64.9 million, with earnings per share of $0.26. While those figures inched above expectations to register a small beat, the larger concern was slowing growth at Synchronoss' largest customer, AT&T.

Now what: Ma Bell comprised roughly 50% of the quarter's total revenue at $32.6 million, while rival carrier Verizon (NYSE: VZ) was the second-largest customer at over 10% of sales. The AT&T business was sequentially flat compared to the fourth quarter, and the company expects AT&T sales to rise between 5% and 10% in 2012. That's lower than the low-double-digit growth it had previously predicted.

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Fool contributor Evan Niu owns shares of AT&T and Verizon Communications, but he holds no other position in any company mentioned. Click here to see his holdings and a short bio. The Motley Fool has a disclosure policy. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. Try any of our Foolish newsletter services free for 30 days.