The law takes a step that is completely unique: it prohibits employers from asking prospective hires about their salary histories until after they make a job offer that includes compensation, unless the applicants voluntarily disclose the information. No other state has such a ban in place.
[...] The new law also bans salary secrecy, blocking employers from keeping their employees from talking about pay with each other. About half of all employees say they are either prohibited or discouraged from discussing compensation, even though they have a legal right to do so.
http://boston.cbslocal.com/2016/08/01/massachusetts-equal-pay-comparable-work-baker-bill/ [cbslocal.com]
http://thinkprogress.org/economy/2016/08/01/3803836/massachusetts-equal-pay/ [thinkprogress.org]