The more users Facebook attracts, the more money it spends — and it's not making it up in volume. That's why Facebook CFO Gideon Yu is reportedly on the hunt for more financing.

Facebook has a voracious need for equipment. Because it stores photos and videos for users, as well as other data, it requires an ever-growing number of servers. The rule of thumb is roughly $1 million for every million users it signs up, according to estimates from people familiar with Facebook's computing requirements.

And the company is still not profitable. Part of the problem: While most of its revenues come from the U.S., most of its user growth has been overseas, where it is just starting to build sizeable sales operations. That explains why Yu is on the hunt for new money, even after raising more than $500 million from the likes of Microsoft and Hong Kong billionaire Li Ka-Shing. It's not clear how much of that warchest is left.

Facebook CEO Mark Zuckerberg hired Yu in 2007 in part for his experience as CFO at YouTube, which financed its racks of video servers with equipment leases from TriplePoint Capital, a Silicon Valley lender. Besides the lease payments, TriplePoint also got warrants — a form of corporate stock option — in YouTube as part of the deal. It profited nicely (as did Yu) when Google bought YouTube for $1.65 billion in 2006. Leases are a relatively cheap way for startups to finance their purchases, and it's common in the Valley for warrants to be part of the deal.

TriplePoint also agreed to finance Facebook's server purchases in exchange for warrants. But when Yu negotiated for a $100 million credit line from TriplePoint last year, we hear that he refused to grant TriplePoint additional warrants.

That stinginess may now be hurting him. BusinessWeek reports that Yu has been seeking financing from Bank of America and other lenders after its line with TriplePoint expired. (Facebook has reportedly used only $60 million of its $100 million line; its expiry means that Facebook must pay down the current balance over time, but can't borrow more against it.) TriplePoint CEO Jim Labe said he hoped to keep working with Facebook. But one has to think he's in a better negotiating position than he was last year, when Facebook was still red-hot and the markets had yet to crash.

Last fall, Yu was also looking to sell shares in Facebook to investors in the Persian Gulf. But that was before the region's wealthy got socked by everything from falling oil prices to Bernie Madoff. Facebook is worth far less than the $15 billion at which Microsoft valued it when the software company invested $240 million in it in 2007 — which means Labe, or any other lender, is in a position to demand tougher terms from Facebook. Stinginess is a good trait in a beancounter-in-chief. But Yu may have overplayed his hand.