Facebook is all the rage these days, what with founder Mark Zuckerberg being Time’s Person of the Year 2010 and the site itself having “changed the way human beings relate to one another on a species-wide scale.”

Sure.

Even better, though, Facebook might actually be making money now according to Bloomberg News:

Facebook 2010 Sales Said Likely to Reach $2 Billion, More Than Estimated

Facebook Inc., the world’s most popular social-networking service, is likely to generate 2010 revenue of about $2 billion, a larger sum than projected earlier, according to three people familiar with the matter.

Sales will more than double from 2009, said the people, who declined to be identified because the privately held company doesn’t disclose revenue. Facebook had $700 million to $800 million in sales last year, and the 2010 figure was previously expected to be closer to $1.5 billion, according to two other people familiar with the matter earlier this year.

But . . .

Here’s what the Wall Street Journal reported last month:

Valuing Facebook’s Ads

The Site Commands 24% of Online Display Ads, but the Dollars Don’t Match

Facebook Inc. is attracting more advertising, but marketers are still trying to figure out the value of those ads.

New data from comScore Inc. show that in September 24% of all online display ads in the U.S. appeared on Facebook—more than twice as many as any other publisher. Yet Facebook is far from capturing a quarter of the wallets of major marketers. The company accounts for just 9.5% of the spending on display ads in the U.S., according to research firm eMarketer Inc.

In other words, Facebook users are extremely desirable, but Facebook advertising is less so.

Here’s the good news, though: Facebook is starting to become the plumbing of the Internet (as someone – I think Steven Johnson – observed about Twitter except it goes double for Facebook).

And you know how much plumbers charge.