I don't read Australian Aviation much however, I do know of the credendials and background of a couplke of contributors.
Dave Prossor writes the Warbirds section. I knew Dave since the 1970's and 80's where he worked as a journalist and also flew gliders and the tugs at Bacchus Marsh. He also worked at Moorabin as a Charter Pilot and is a Flying instructor.
Owen Zupp was at Ansett as a B737 FO when the music stopped. He is now at QF flying as an FO on something.
Aviation 'commentator' might be the term to apply to Ben Sandilands and Geoff Thomas. This is not meant in a derogatory way, informed commentry is an essential component of news and current affairs coverage.
In the legal arena, the differentiation between a witness and an 'expert' witness is that an expert can provide opinions and conclusions that a jury can be directed to take into account in reaching a verdict; an ordinary witness can only state what they observed.
Ordinarily, an expert witness would be a professional in a particular field. They would hold some formal qualification be it as a Trade qualification or a PhD. The higher the qualification, the stronger the weight of their evidence. However, there are experts and there are "experts"- Lindy Chamberlain was convicted of murder on the flawed evidence provided by a BSc Qualified Lab Technician and by a Professor of Forensic Science.
Of concern:
"Most of us are uncomfortable with the idea of being perceived as experts. In a traditional sense, an expert has engaged in years of research and has likely been published and scrutinized (in an academic sense).
Social networks and new media, such as blogs and Podcasts, have resulted in a new surge of perceived experts. This is because of two things:- consumer power to make choice is greater now than it has ever been
- people are able to translate their passion into a communicable form for mass consumption
"Rightly or wrongly, the term “expert” is no longer exclusive; it’s now used to describe those who can magnetize an audience. Experts are now designated by niche communities based on an ability to communicate opinions, ideas, experiences and passion. You can do any amount of research, or none at all, and still be seen as an expert..."-M. Blevis.