Somebody did a fine bait and switch job when the Snowden revelations first came out. I say fine, because it seems that most people never noticed it. This was the characterization of data about phone calls, emails, etc., like phone numbers and headers, as "meta" data. Sounds really comforting, because it isn't really data that they're taking, but something a bit fuzzier. This term has been picked up and used by pro- and anti-NSA articles and diaries and comments, and every time it's used, it softens the arguments against the ubiquitous snooping that's going on.
Update: It's been pointed out to me that I used the term metadata when I was talking about statistics, rather than correctly.
Information about information; more specifically, information about the meaning of other data.
http://www.thefreedictionary.com/...
This is a representative definition. Having now checked a few other definitions online, I'm still inclined to include statistical manipulation of data into the metadata category.
Metadata is what you get from Nate Silver, when he takes the data he has and massages it to show political trends. Metadata is what shows up when kos points out current site statistics. It takes the data that's been collected and massages it to show, well, whatever the data collector can pull from analysis of the data.
Longevity trends are metadata. So are the graphs showing the rise in economic disparity. The phone number of a caller and the header on an email are data. Your experiences, good or bad, are not "anecdotal", they are data. They don't necessarily signify which way things are going overall, until someone records and collates them into some larger picture: metadata. Most of the time that I see people on this site calling for "real" data rather than "anecdotal" data, they're in fact calling for metadata.
You can't collect metadata. (Well, you can - HuffPo and others collect various polls to compare and contrast them, but this requires someone to have previously done the analysis that creates the metadata.) Whoever first used the "we're only collecting metadata" meme did a good job confusing the issue.
I realize that the current revelations and discussion have gone well beyond the metadata arguments, but I'm still seeing the word used in almost every article on the subject, and I think it skews the arguments every time it's used.
Rant over.