It's very profitable.

Once upon a time they used to simply monitor the private jets of big execs. When one filed a flightplan as required by law they could see which country the meeting was happening in, who else was going, and figure out if something big might be happening.

Now it's just a matter of picking up on a few of the thousands of ways we "leak" our activities online.

ALERT "Bill Gates's mobile device and the mobile device of the president of *insert country here* were in close proximity for 47 minutes this morning".... this is why privacy matters.

Chuckles ... I avoid all the above (linked article in OP) and NoScript the rest. Call me recalcitrant ... I do not play well with others (webmasters) as a user.

Call it a hedge against privacy. :)