I posted a thread to the WF Adsense SEO Sub-Forum earlier today to announce an article where Danny Sullivan verified that Google and Bing are in fact tracking Twitter and Facebook and giving "some" SEO value to links placed there, regardless of whether the link carries NoFollow or not.

I have long suspected Google and Bing would play this way, but the Sullivan article verified the information for me for the first time.

That thread can be seen here:
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