That’s revenue, not profit, because they are a not-for-profit entity. Their financial statement shows what a sensible, conservative operation they are, and I look forward to seeing what they will do with the tens of millions of dollars and convertible assets they now have.
This is a great example of how to create a successful business via giving away a product - FireFox. The revenue is mostly from Google, who pay them search royalties from when users search using the default search function. So to help FireFox stay popular, and force IE to keep improving, use that search box! Or buy a t-shirt.
Just because your business is non-profit, doesn’t mean you can’t pay yourself a good salary - although Mozilla don’t seem to be paying a fortune to any of their 90 programmers - they average $200K each, which is probably about right.

And remember, if you are non-profit, and do good not evil, many people will choose to use you over Microsoft et al