People oversell this tracking/advertising. It's not a goldmine for every site. For this blog, if she wanted to include analytics into her decision about what content to produce, does she really need super high resolution stuff like where people moved their mouse? Would she ever make a significant income from these "ads", or selling the data for possibly pennies?
Besides, just google analytics or something like that wouldn't be that bad (I know the blog author would disagree). A lot of sites go nuts and have like 20 different trackers that probably track the same things. People just tack stuff on, YAGNI be damned, that's a big part of the problem and it's a net drain on both parties.