When Microsoft said last year that it's committed to protecting its customers from government data requests, it wasn't messing around. Microsoft general counsel and executive VP Brad Smith recently revealed that the software giant successfully challenged an FBI National Security Letter that tried to seek basic information from one of its enterprise customers. The letter apparently had a nondisclosure provision that would've prevented Microsoft from telling the customer in question about the request. Microsoft challenged that provision in Seattle's Federal Court, stating that it was "unlawful and violated our Constitutional right to free expression," and wouldn't you know it, the FBI withdrew the letter. Smith said in a blog post that such requests are rare, but it's still good to know the Redmond company is continuing to do what it can to be transparent about such things -- even if it knew about them all along.