Fog Creek's salaries are transparent to employees. Spolsky explains how they deal with the qualified new hire who expects a higher-than-market salary: (http://www.inc.com/magazine/20090401/how-hard-could-it-be-em...)

Personally, I've shared my salary with like-minded coworkers willing to help each other negotiate the best terms. Never shared with most people, however, because they've internalized irrational ideological barriers to doing things like this.