My first job out of college-the-second-time, I started at minimum...got a seven cent raise 30 days later.

A few years later, I was at a coworker's house because his wife babysat for me. They were discussing paying bills, and despite being careful not to mention $$, it was obvious from the conversation that the co-worker made double what I made, doing the same job. I mentioned that to my supervisor once, making it clear that the coworker had not ever told me his wage...and was told it was because this guy had "more experience." This was true, he'd been working for ONE YEAR longer in the field. Needless to say, my next raise didn't come anywhere near to doubling my wages, even though I'd been there another year.

When I found another job, they instantly offered to raise my wages by nearly $3 an hour, which was more than the new job, but I figured I'd never get another raise without quitting again, so walked. A different coworker later asked me how much the new job paid, and I told him. He couldn't understand why I took "such a cut in pay." So I told him what I had been making...doing the same job as he, with 2 years less experience. I didn't ask what he made, the look on his face was enough.
When companies restrict employees from mentioning wages, there is a reason. I'm not saying they don't have the right to do it, but I am grateful I have the right to find a better job, too.
