Since Mozilla Foundation released their 2007 financial report, the meddlesome folks at the Internal Revenue Service would like to take a better look at the organization's tax exempt status.

The IRS are due to perform an audit on Mozilla, who runs the popular Firefox browser, and their relationship with Google.

Last year, Mozilla received $66 million from Google, which makes up a wopping 88% of their total $75 million revenue.

In 2006, they received $59.5 million from Google, which was about 85% of their revenue.

Tax exemption is granted to an individual or an organization which the government wants to promote economically, generally like a charity; and it's usually meant to reduce the tax burden in the interest of fairness or to promote some type of economic activity through the reduction of tax burden on that organization.

So if the IRS deems Mozilla isn't up to par with their definition of what a tax exemption means, they could conceivably  get this status stripped.

Source