So far, The New York Times (NYSE: NYT), Penguin, Harper Collin, Simon + Schuster, Hachette and MacMillan are all officially drinking the iPad Kool-Aid. Conde Nast, Hearst and Time (NYSE: TWX) Inc are not far behind with iPad apps planned or already being built. There will have been countless meetings and water-cooler chats, at software and media agencies, in the last week to plan the ”iPad strategy.”

As well as an app development environment, Apple (NSDQ: AAPL) is delivering a mature payment platform and storefront to sell content. It takes a long time to a get a digital retail platform and user experience right. Apple has been doing this since 2001. Even Google (NSDQ: GOOG) has suffered here, with Checkout being a stand-out technical failure. iTunes has 125 million accounts with authorised credit cards against their name, just a few clicks away from buying an app in the iPad App Store or the next JK Rowling in iBooks. But builder, beware…

The sacred fruit does not come for free

Apple understands the economic value of controlling the hardware, development environment, billing relationship and retail channel. This is the pay-back it extracts in return for the risk of its vertically integrated production and design strategy…

—In 2001, Apple gave the music industry the retail platform for digital music it was looking for. In exchange, Apple took control of their business.

—In 2007, Apple gave the mobile industry the handset that justified the use case for mobile data networks, and in exchange demanded an unprecedented share of contract revenues from its launch operator partners, AT&T (NYSE: T) and O2.

—Today, Apple takes a 30 percent share of revenues from all paid applications in the app store. Advertising is the only service line delivered over iPhone or iPod devices in which Apple does not demand a cut, but the recent acquisition of mobile ad network Quattro Wireless suggests that this is a temporary portfolio gap.

Media companies looking to embrace Apple’s three controlled iPad channels (App Store, iTunes, iBooks) should do so with some caution and be wise to acknowledge the power Apple now has over the music industry. Book publishers at least do seem to be aware of this, and have a stalking horse in the form of Amazon (NSDQ: AMZN), Barnes & Noble (NYSE: BKS) and News Corp (NYSE: NWS). which may or may not announce its own rival tablet device.

Will the buying public swallow a tablet called the iPad?

The second major caveat is that the paid content and advertising revenue opportunity for the iPad is a function of the device volume...

The iPhone took time to ramp beyond being a device for Apple enthusiasts and this was selling into a very well established product category. The iPad is Apple’s “do everything” device (netbook, smartphone, iPod, and potentially television) but faces the possibility of not meaning anything to anyone beyond the “iBuy” market.

The key to Apple’s go-to-market strategy for the tablet form factor, and what will differentiate it from previous efforts from Sony (NYSE: SNE), Microsoft (NSDQ: MSFT) and HP, among many others, is: branded content partnerships; iTunes; the full library of applications already available on the App Store that can port directly to the iPad; and a community of developers with Objective C skills chasing the dream of creating the iPad’s equivalent to the iFart application, which hit $10,000 a day in download revenue on the iPhone app store back in 2008.

As the installed base of iTunes and iPod users created a natural market for the iPhone, so the base of iPhone, App Store and iTunes users will create an audience for the iPad. However a better web browsing experience, a new iTunes controller and some new digital photo frame functionality are not going to be enough to sell this device. Branded content partnerships an innovative iPad-specific applications are going to be critical for Apple creating mass market demand for the iPad.

This creates an interesting point of leverage for media companies with market-making brands and content. They have the opportunity to create commercial frameworks with Apple today that will allow them to participate in possible future growth in this category, without some of the regret the music industry now has in being nickel and dimed in 2001.

To translate this to a media revenue opportunity, the market will be eagerly watching for App Store, iTunes, eBook, and advertising average revenue per user (ARPU) data as the devices start shipping…

But a key problem may prove to be the sheer number of applications available for the iPad. Even the biggest brands will have difficultly surfacing their apps in a market of the 300,000 titles forecast by the end of the year. The fight for what may be just around $5 ARPU per month will be fierce.

So is the iPad a great white hope for media? Yes – if Apple can get it to critical mass and establish the category. But competition for share of the revenue available is going to be fierce, and volumes are going to take time to ramp…

Any publisher that it betting that this shiny device alone will save their P&L has probably already failed.