So it probably means that a school is OK if I cant find any negatives reviews about a school on the internet?

Not quite. The advertisement from the school can also tell you quite a lot.

The salary level, expected hours, visa type etc. Does the school try to show off its educational prowess or its 'cute kids?'

Does it use words in the school's name like 'Oxford', 'Cambridge', 'Harvard', 'American', 'Canada', 'Eton' etc.? Then it probably has nothing to do with the said institution or country.

We often catch out bullshit positive reviews on here through such methods, a fake review never tends to discuss a school's educational qualities, just supposedly high pay, low working hours etc. Things that wouldn't be at the top of the list for anybody that cares about education at all.

Usually nobody praises people for doing what they are supposed to do. That is why most reviews are bad.

Public schools and unis are usually far more legit. Why will you never see a review from the very best unis? Because they don’t hire teachers for a one year holiday and they don’t mess anybody around.

In fact that is where the reviews system arguably fails on every other ESL website. In what other kind of industry would anybody review the job that they have just left TripAdvisor style? Who ever feels happy after leaving a job that they like? Apart from professional athletes who sign up for megabucks deals, who the hell publicly announces renewing a contract?