[belorn]

At this point in history, tracking on the web is no longer a trusted activity where people can assume that the person behind the tracking is doing it for benevolent purposes. It's the same thing with email and spam, especially when attachments are involved.

Writing your own analytics can give some additional benefits in that you are only collected what you need while taking into considerations your users needs. I expect however that in time browsers will block more and more by default, similar in how email clients and services has progressed in their arm race with spam.