WWDC has always been unique for having dual identities: developer conference and consumer event. Attendees seek technical knowledge that’s not applicable to most people, while the keynote announcements draw interest from millions around the world. Other developer events such as GDC do have consumer impact, but don’t enjoy nearly as much coverage in the mainstream media.

This year, however, Google I/O rose to that level, with announcements of both new and upgraded consumer products drawing strong publicity. Its keynote rhetoric also highlighted the intensity of the now full-blown rivalry between Apple and Google. As expected, Apple fired back in the WWDC keynote last Monday, with varying degrees of subtlety.

It’s important to note that Apple does not frequently acknowledge competing products when discussing its own; the keynotes and special events typically promote the strengths of the product alone. A significant amount of last Monday’s keynote content was, by contrast, clearly influenced by competitive pressure.

The breakdown of mobile market share was predictable and direct. The financials were there, as always, to show developers that iPhone is a platform worth investing in. But the third party demos were telling. Apple often chooses these demos carefully to showcase specific new Apple hardware or software features. Not so this year: the chosen demos did nothing new and were not using iPhone 4 or iOS 4. They were simply leading brands, all in the entertainment space, that consumers recognize and respond to. (Yes, including Farmville.) Rather than “look what iPhone can do,” these demos said “look what iPhone’s got.” It’s a notable difference in message, presumably driven at least in part by the new competitive landscape.

Steve Jobs also spent a lot of time Monday deflecting heavy criticism of Apple for not being “open” enough. The first point made to this end was a clear differentiation between the open web — which Apple not only supports but continues to drive — and the “curated” native App Store. The use of “curated” was very deliberate, and a direct response to the much more negative “closed” thrown around lately. Look for it in future statements and interviews until criticism subsides. Meanwhile, developments in Safari and WebKit continue to raise the bar for standards-based web apps.

The introduction of Bing as a search provider for Safari on iPhone had been rumored for some time. Naturally, everyone saw this development as an attack on Google. But the presentation itself sent just as much of a message. Jobs used the word “choice” six times in less than twenty seconds during the Bing announcement. While Apple’s addition of Bing was a shot at Google’s core business, the announcement was a shot at its melodramatic PR.

One can’t help but appreciate the irony here. The initial friendship between Apple and Google was surely inspired in part by a common rival in Microsoft. Now the tables have turned, with Apple and Microsoft sharing the stage against Google. The reversal is so severe that a busted Bing demo in a later session drew heavy applause upon finally working. A WWDC audience would not have been so kind to Microsoft in earlier years.

The announcement that FaceTime would be an open standard was another surprise. Would Apple have done this without the pressure Google and Adobe have been applying? Maybe. But we certainly wouldn’t have seen a slide with a giant “OPEN” on it.

Finally, the free iOS 4 upgrade should give Apple some high ground on Android among developers. This is the first time iPod touch users have not had to pay for a major OS upgrade, thanks in part to looser accounting rules. But too much is at stake, and Android’s fragmented installed base will become a louder talking point. Apple wants every customer on 4.0 as soon as possible, and wants every developer to know that it’s safe to move forward without looking back. Don’t be surprised if Apple becomes unusually vocal about the number of users running 4.0.

Probably the biggest takeaway from the keynote, though, was the lack of a supporting cast for the first time in many years. No Phil. No Scott. No Bertrand. Steve Jobs is back, and back in charge, and nobody else was going to deliver the news or the message under this kind of pressure.

The battle continues to heat up. With both words and actions, Apple is taking the competition very seriously.