I’m stumped on this one, what data is exactly being shared with Google, through my Analytics account?  Obviously it only shares data via sites that have the Analytic code installed, what the paranoid little man in me wants to deny any access.  This is especially true for my sites earning large amounts of scrilla through Adsense, where they could peek into what keywords are scoring highest for me and either slap me or hold me up.

Furthermore, they are requiring your data to be shared with them to gain access to soon to be standard Google features.  The Google Analytics FAQ in regards to Data Sharing specifically states that you MUST share your data with Google to gain access to their upcoming Adwords Conversion Optimizer.

The Analytics FAQ does address one of my ranking concerns, but not directly.

Your website data will not be used to affect your natural search results, ad quality score or ad placement. Aggregate data across many customers will be used to improve our products and services.

Just because you’re not paranoid doesn’t mean they’re not after you.  Lastly, make sure you do not automatically share your data with an ambigous ‘Others’.  Of your two choices when sharing your Analytics data, Anonymously With Google and Others is an option.  I wonder how much it costs to get a hold of that information?