[pyre]

Pooling all of that information into one place is begging for it to be abused. Would you still be asking the same question if it was s/Facebook/NSA/g or s/Google/FBI/g or even s/Google/KGB/g? Once all of this information is in place how hard do you think it will be for such organizations to get access to it? Just because the 'big bad guberment' isn't the one doing the collecting doesn't mean that the information cannot be abused internally, or externally to the company compiling it.

[revorad]

Usually these discussions sound like some people are worried that the corporations themselves will do something bad with the data (sell you more stuff you like !gasp!).

Government misusing data is the only thing I could think of. But what's the evidence for that fear? If the organisations you mention wanted to go after people, can't they already do so?

With this kind of reasoning, the internet itself should qualify as a huge setback to privacy. The point is that the advantages far outweigh the disadvantages.