It didn’t garner much attention, but earlier this month, the chairman of a Fortune 500 company was kicked out of his job, and it wasn’t by management. Shareholders voted out Ray Irani, the chairman and former CEO of Occidental Petroleum, at the company’s annual meeting, with 76 percent of investors denying Irani the post. Irani had planned to retire in 2014, but criticism of his outsized compensation package—he averaged over $80 million in annual salary over the past decade—and questions about his using the board to attempt to replace his successor, CEO Stephen Chazen, led to an early demise.

The Irani ouster was the latest in a flood of shareholder activism, hitting annual meetings of the largest publicly traded companies in America over the past several years. Over 600 shareholder proposals have been filed this year, including a vote by JPMorgan Chase shareholders on May 21 on whether to split the positions of CEO and chairman, which would ensure that Jamie Dimon does not hold both.

If this sounds like democracy in action, with shareholders expressing their preferences for the companies they own, and making their voices heard, that’s because it is. But it’s a very peculiar, American-style democracy, complete with unequal representation, lobbying, attempts to rig or delay voting and a byzantine set of rules. For that reason, it has often been often ineffective; but recently, activists have deciphered how to navigate this process and are increasingly changing corporate behavior. Across all types of proposals, activists have been very successful this year. As of April, activists won 66 percent of all proposal votes, compared to 51 percent in 2012.

Shareholder activism, which includes everything from union pension funds and socially responsible investors to hedge funds staging hostile takeovers of corporate boards, dates back to the 1940s, and the SEC’s adoption of Rule 14a-8. Under the rules, anyone with $2,000 worth of shares can file what is known as a proposal, which can get a vote at the annual shareholder’s meeting. “It provides a valuable opportunity for shareholders to convey concerns to management,” said Brandon Rees, the acting director of the AFL-CIO’s Office of Investment.

Most early proposals had to do with corporate governance, but the 1970s brought the first proposals on social issues, such as divestment from South Africa or environmental responsibility. Over time, however, socially responsible investors began focusing on corporate governance: the best way to get a CEO’s attention on an issue was by threatening to replace him. “I was head of corporate affairs for the Teamsters, blasting out proposals,” said Bartlett Naylor, now with Public Citizen. “I realized that you can’t get anywhere with ‘Be nice to your employees.’ But when we filed a proposal about splitting the chair and the CEO, it was amazing how the corporate secretary would want to come down to the Teamster offices and see what our concerns were.”