While I am supportive of this, I expect a lot (majority?) of listings with ranges like "$40k-200k based on experience". (Or the example from the article, "$17-50/hr")
Something like this is an extreme range (clearly no one in engineering would be at 40k) and would make the employer look quite bad IMO.
FWIW GitHub https://github.com/about/careers has eng salaries for US positions be like "min 110 max 250" and while the range is high, it's still more useful than no information at all IMO.
I wonder though how this would look like for non-tech jobs.