I love great tools. Andrew Wong of 6dgree.com recently contaced me and showed me a new tool that I think has a lot of potential.
Persona (update: site no longer open, perhaps this tool disappeared.) allows you to track demographic data for your website visitors. It does so by integrating with Sina Weibo. Anybody that is logged in to Sina Weibo when they visit your website can be tracked. Persona then gives you both agregate data and data on the specific users that visited your site.
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