Tonight, the world will be watching as Apple announces the iPhone 5. Swept away amid the headlines may be some interesting tidbits to keep track of. Here's what keen investors should keep an eye out for.

Tonight, the world will be watching as Apple announces the iPhone 5.[Internet photo]

1. Fun facts and stats

Apple likes to take these opportunities to tout figures and stats that only Apple knows, such as the digits it gave at its Worldwide Developers Conference. Those included the fact that Apple now has 400 million active iTunes accounts, complete with credit cards just a tap away, cuing speculation about when Apple would launch a mobile payments service to challenge Google Wallet.

Then there was the revelation that it had reached a cumulative developer payout of US$5 billion in June. That figure was just US$4 billion in January, and subsequently reached US$5.5 billion in July. This metric is meaningful on several levels, including a monetary one. Since the iPhone maker keeps a 30% cut while passing along the remaining 70% to developers, that means Apple has brought in US$2.35 billion in revenue from App Store purchases since 2008.

Any stats Apple chooses to share might even hint at how it will fare this quarter. For example, if the company decides to tell us its running tally of cumulative iPhone units sold to date, we could cross-reference that with the fact that it had sold 244.2 million iPhones through last quarter, and the difference would be this quarter's sales to date.

If Apple discloses lifetime iOS devices sold, which it likes to do on conference calls, we could similarly back into iPod touch cumulative unit sales, which Apple doesn't disclose specifically. There are all sorts of numbers games we can play. It just depends on what numbers Apple might give investors tonight.