Sina isn't a household name in the US, but its shares trade more than Google and nearly as much as Apple.

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In an earnings conference call in February, Sina Chief Executive Charles Chao warned that the company wouldn't be able to convert all of its users by Friday, and said Sina is "working with the applicable regulatory bodies" on implementing the verification procedures.

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As for the blog de mode, sina.com's Twitter-like service, Ms. Xu isn't interested.

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Sina's counterpart Netease, a community-based portal which listed last week, wasn't that successful.

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Others have noted that authorities in Jiangsu didn't publicize the cases there until after a hospital record purporting to document a local H7N9 infection was posted on Sina Weibo.

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