In this answer is was treated as unusual that salaries are kept private in the company in question. Frankly, I'd never actually heard of a company making it's salaries public, beyond non-profit organisations. I live in UK which might explain this if it's a culture difference. I'm curious to know how common it is.
Are any data/statistics available? Are there countries in which salaries are public by default?
Public Sector
In many countries certain public sector companies are required to make documents public. The specifics vary dramatically location to location, but often these include budgetary items such as staff wages. (Needless to say, where it's legally required it's done)
Private Sector by requirement
Some private sector companies have legal requirements to disclose budgetary items such as staff wages. Typically though this is companies who's primary income comes from government grants and contracts. This also varies dramatically place to place.
Private Sector Optionally
Some private sector companies do make their wages public, however; this isn't very common. In regards to public and private wages honestly from working in multiple companies who's wages were public for legal reasons it really didn't affect your pay or turn over much.
People tend to think public wages means everyone will go "John gets paid more, I'm better than John, I should get paid more" fact is, if you go to your manager with that sort of argument for a raise you're going to be sorely disappointed. (Just as you would if wages weren't public but you over heard John mentioning his wage) The way for successful negotiating is demonstrating you're worth more to me than I'm paying you for.
That said there are managers who do well with public wages, and some who don't handle it tactfully.
Public wage concerns
The only really big concern with public wages is if a company isn't paying people fairly. Such as paying below minimum wage, or docking salary employees pay based on hours, or paying staff less based on gender, religion, or race.
So the reality isn't the wage being public is a problem in itself, rather if you have bigger fundamental problems they become public knowledge as well which can hurt your public image or even get your company in legal hot water.
I'm in the USA and have worked for around 10 different companies. In that time, there has only been one in which everyone knew what everyone else was making. It was a small start up with 5 people, all of which were co-owners, so I'm not 100% sure that counts. At least one of the places I worked at everyone had well defined job titles in which the salary ranges for those titles were well known.
However most of the places I worked at kept salary information private and it was requested to stay that way in the employee manual.
I disagree with RualStorage's statement that "The only really big concern with public wages is if a company isn't paying people fairly." My experience has been that "fair" is a very subjective statement and completely depends upon the person making it.
I've seen coworkers compare salaries and invariably all of them end up unhappy. The Sr guy is unhappy because he thinks he ought to be making even more than the Jr guy than he currently is. The Jr guy is unhappy because he thinks he does the same work as the Sr guy and that the extra 5 years of experience doesn't matter. Two people at the same level are unhappy because, well, each of them think they are worth more than the other even if they do have a similar background and job description.
Many places that publish salaries give a range for each job title that often includes sub levels. i.e.: Programmer II or Sr. Analyst III. The sub levels give the hiring managers the ability to play with the salary they are hiring a new person in at while giving the pretense that everyone is being treated "fairly". Often there are well defined ways of moving between levels; however the requirements for being hired into a specific one changes as the needs of the company does.
Point is, even the places with "published" salaries are as opaque as anyone well with plenty of wiggle room.
This might not be exactly what you're looking for. But in Sweden, where I live, everything that can be available to the public is.
This means that people's salaries, school grades, etc. are available to the public. Although you have to request them.
I however doubt that the situation is the same in other countries (judging by the other answers).
Companies themselves do not publish the salaries, so it only does fit the title of your question, but not its body.
Fun fact: The information about salaries is updated around April/May each year (when the taxes for the past year are determined). Sometime during this period some of the biggest newspapers publish lists like "Here are the richest people in your area".
The answer you link so has some problems. The main one is that it fails to distinguish between "making individual salaries public" and "forbidding employees from discussing their own salary".
It is extremely rare that a company makes the salaries of its individual employees public, in the sense that anyone can find them out. Salary information is private between employer and employee. The exceptions to this are 1) very senior managers in a public company 2) senior managers in public corporations 3) many public sector employees in the USA. In all cases it's accepted by the employee that their salary will be made public.
Some companies also try to enforce a ban any any employees discussing their own salaries. Bans like this are almost never enforceable, but some companies try hard to do so, and will take punitive actions against employees who talk publicly about their salary.
User lilienthal's comment is on the money with regard to the answer you link to. Leaking individual's salaries without their consent is a serious breach of confidentiality.
