Disclosing your salary to fellow employees helps them by increasing their ability to bargain effectively with their employer. (and disclosing salaries to each other helps both of you)

Similarly, disclosing your salary to a potential employer helps them by increasing their ability to bargain effectively with you.

The intent of the #talkpay movement was to identify disparities between employees of the same position, possibly due to extrinsic factors like gender: http://www.buzzfeed.com/carolineodonovan/talkpay-topped-twit...

This article is more about negotiation.

Disclosing to everyone would do away with the issues raised by the article. If everyone knew everyone's salary, there would be no underwater price-fixing scheme, and disclosing to recruiters would do no harm to you and your colleagues' negotiating positions.

The Twitter movement was about gathering information so that those who are underpaid can realize how underpaid they are and potentially change that.

This post seems to be more about at a personal level, and not giving in when the salary negotiations start.

#demagoguery