Those things are much more appropriately addressed by targeted usability testing (eg in lab studies) where participants are aware of, accept, and are compensate

Those things are much more appropriately addressed by targeted usability testing (eg in lab studies) where participants are aware of, accept, and are compensated for being monitored. Not by mass surveillance. The perspective expressed, basically that anything is acceptable as a means to optimise "user experience" (most likely so more money can be extracted) verges on unethical and immoral, if the bigger issues of group and individual privacy rights are considered. Nevertheless, as a web developer you are most likely only gathering stats from your particular web site, which is a different kettle of fish to browsers gathering and aggregating data across many sites.