Wikipedia is one of the most popular websites in the world, the fifth most popular by some counts.
Yet it's one of the very few top sites that isn't a company and is not motivated by profit. Instead, Wikipedia aims to make knowledge as widely available as possible. Granted, it needs money too, but it raises everything it needs from donations.
It also stays frugal, despite being a top five site, Wikipedia operates with a budget [PDF] of under $30 million, €22.66 million a fraction of what any of the other comparable sites spend.
The site got $35 million, €26.44 in donations last year, out of a total revenue of $38.5 million, €29. More than 1.1 million people donated to the site in last year's campaign, the vast majority of them small sums.
The word is that this year's campaign, the results for which will be announced soon enough, has been even more successful.