The department said the profile was backdated to 2008 to avoid having to merge data from an old IT system and a new one.

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You have to figure out how to merge store data, financial data, customer shopping data, online data, and so on.

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There are mashups that let you see which products are selling best on eBay , that help manage the sale of foreclosed property through a network of real estate agents, or merge sales information with data mining from analysis firm Business Objects .

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Proper usage: When two companies merge, the pro forma data give shareholders a point of comparison from one year to the next.

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She also says that, while Acxiom does store personally identifiable information, it doesn't store or merge anonymous online-tracking data, such as Web-browsing records.

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