I think if you read the article closely it's fairly easy to tell if the author knows what they are talking about. Beginners tend to gloss over intricate details and focus on the basics, where experts tend to focus on the intricate details and skip over the basics.

If you have knowledge of the subject matter, then it's easy to see if an author knows what they are talking about, but if you are a beginner, it is fairly common on the internet to have articles, tutorials, and videos, where the author just learned the subject themselves and are now repeating the information they themselves don't fully understand, and are accidentally mixing in wrong information with the correct information. The beginners can't detect it, so they believe the good and the bad.

Peer-review is important, but should an article that is 90% correct be rejected because it is 10% wrong? On the other hand, should the 10% wrong be allowed to continue to exist while waiting for the original author to fix it? The peer-reviewers should be able to edit articles, and the original author and other peer-reviewers should be able to see the history of edits, and the author should be informed of the edit. Even easy-to-make mistakes might misinform a beginner for years to come, and the sooner those mistakes are caught, the better.

I don't think that biographical info or "expert" tags are going to solve the issue of establishing authority. I actually worry that labeling someone as an authority on a particular subject will lure us into a false sense of security, where we take their word as gospel and fail to notice mistakes or scrutinize their content as closely as we would, say, a new member of the site without an established background. Nobody's perfect, and as Servant of the Lord pointed out, misinformation gleaned as a beginner can persist for years, even as this individual goes on to become a supposed expert and begins handing out potentially incorrect advice to others and being taken at their word, so it's never safe to assume that even a labeled expert knows what they're talking about 100% of the time. That being said, I'm not strictly against the idea of tags, because there are certainly users who have demonstrated that they know a particular field quite well and their knowledge should carry some weight, just so long as we remain vigilant during the review process and not pass any premature judgement based on such tags.

At the end of the day though, I am perfectly happy with a peer-review system where any individual with well-constructed feedback (with or without verified credentials) can weigh in on the validity or correctness of an article, and discussion/edits can take place until the editor-in-chief (Mike?) deems that the article has been peer-reviewed sufficiently and can be tagged as such. If the author (or reviewer) happens to be talking out their ass, then the process will shed light on that quickly enough without needing any expert stamp of approval. Likewise, if an error or two does happen to slip through the cracks, then readers can certainly comment on the article and point out these errors. After all, this isn't a StackExchange-style site where discussion is discouraged in favor of a strict question and answer format... it's quite to the contrary. If anything, this commentary because supplementary to the article itself and can provide just as much useful knowledge as the article itself.