Five years ago, on June 29, 2007, the computing world changed forever. What was this landmark moment? The iPhone made its debut.

I can already hear keys being tapped as incensed readers type, "The computing world changed forever? Hyperbolic much?" or "Just another Apple fanboi."

I'm not an Apple fanboi (or fangirl), but I am someone who has been around the industry long enough (and then some) to have seen the debut of the iPhone; to have heard people say that no one needed or wanted such an expensive, precious device; and to have seen IT departments actively block its entry into their organizations. (A column I wrote about it at the time was titled--I thought quite cleverly--"Will the iPhone Be an iNightmare?")

But I have also seen the iPhone take hold like no other device before it and change the way we think about personal mobile technology. I have noted the influence it has had on pretty much every device--mobile or otherwise--released after it, not to mention the fact that it pretty much created the app market and changed the way we interact with, purchase and update our systems (love it or hate it, iTunes, anyone?).

I would also venture to say that the iPhone helped pave the way for the widespread use of social networking platforms and the culture of sharing just about everything. The iPhone just made it really easy to do so.

That is not to say that the iPhone is, or ever was, perfect.

Expensive? Check.

Resource-hogging? Check.

Fragile? Check.

Proprietary? Check.

The iPhone was introduced by Steve Jobs, six months before the device's actual release. Here's what InformationWeek said in a story published around that time:

"The consumer electronics product that captured the most attention at the 2007 International Consumer Electronic Show wasn't even at the show. The buzz surrounding Apple's new iPhone reverberated throughout the halls of the massive show because of its potential to shake up the mobile device market by combining phone, Web access and the traditional iPod music player into one sleek product."

Contrast that with InformationWeek's recent vetting of predictions for the iPhone 5, expected to be released this fall. Rumor has it that the new iPhone will be longer than the current iPhone 4s (likely, says InformationWeek's Jeff Bertolucci) and thinner than a credit card (not likely), will have a curved design and a liquid-metal case (not likely), will sport a quad-core CPU (likely), and will have a smaller dock port (likely).

So, if the iPhone is so important, how much do you know about the very first one? Test your knowledge by clicking through our slideshow.