One of the reasons that Silicon Valley has a decent record of overcoming discrimination (though of course it still exists) is that entrepreneurship offers a self-made path to success.
If the old boys club thinks women or minorities can't be CEOs, there's a simple answer--start your own company.
Once there are prominent, successful women/African-American/you-name-it founder/CEOs, the path is opened for those that come afterwards to be picked as CEO.
Marissa Meyer's recent appointment as Yahoo! CEO is a great sign of progress for women in tech, but this story of Liz Pearce's appointment as CEO of Liquid Planner is even greater.
Liz isn't a celebrity. She didn't start the company. She joined the company at age 30, after being a consultant. Sure, she's got a great track record, having worked her way up at Sony, Google, and Amazon, but that's what you'd expect from a CEO.
There's nothing in Liz' background or the story on her appointment that jumps out or is trumpeted as progress.
And that's the true sign of progress.