Everyone knows that how Page rank played a pivotal role, back in the day.
Nobody knows exactly how PR works today apart from Google. Don't worry about chasing it too much as it, and REPUTATION, which is more important, comes naturally as a result of getting links to quality in-depth content from reputable sites, over a sensible period of time.
As marketers, measurement is key to showing our success and more importantly duplicating our efforts in the future. Like Page Rank, trust flow can and should be measured.
Thanks - BB.