Up until a few years ago, Apple CEO Steve Jobs and Google founders Sergey Brin and Larry Page enjoyed an amicable relationship. Brin and Page were so impressed with Jobs they wanted him to be Google’s CEO in 1999, according to a new book about Google, In the Plex: How Google Thinks, Works and Shapes Our Lives by Steven Levy.

At MacWorld 2007, Google CEO Eric Schmidt joined Jobs onstage and extolled the symbiotic relationship the companies have. Schmidt said what he liked about the Internet is you can merge without merging, and each company should do the absolutely best thing they can do every time.

But by the time Jobs visited Google’s facility one year later, the relationship between the companies had drastically changed. The cooperative nature of the relationship had turned fiercely competitive, and it was the result of both companies entering the smartphone market.

Jobs became angry when he saw a prototype of Android with pinch and zoom features, and chose to keep the development of the iPad a secret from Schmidt, who was also on Apple’s board of directors at the time, Levy dishes in his book.

Whether or not that’s exactly how the situation played out, we’ll probably never know. But Levy’s story highlights an ongoing characteristic of cutting edge technologies. There’s a fine line between being inspired by another’s work, and blatantly ripping it off and calling it your own. And this can often be a murky area at best.

Phone manufacturers, software developers and mobile service providers all have a vested interest in cooperating in order to provide consumers with compatible and easy-to-use smartphones. To that end ,they need to share information with each other. But what information is shared and when is a calculated decision, driven by the need to tightly guard industry secrets from being leaked too soon or to an extent that they may be replicated without consent or compensation.

Apple and Google both have reputations of fiercely guarding intellectual properties, and the apparent rift between Jobs and Schmidt as described by Levy is not likely to be an isolated incident as these two juggernauts continue to carve up technology markets.

What would likely be best for consumers to have access to the best quality products and services at the most reasonable costs would be for there to be a balanced mix of competition and cooperation among Apple, Google and other companies.

The iPhone and the Droid more or less embody these ideas in a sense. Everything Apple is strictly proprietary, and the company’s administration of the iTunes and App stores is a good example of its isolationist and aggressive view of ownership and control.

Google, on the other hand, made its splash with search, an activity that requires cooperation in order to function. Android phones are available in multiple shapes and sizes.

It will be interesting to see how the relationship between these companies and others plays out in the next 10 years. Will they be forced to work together and share more, or will the name of the game be keep it a closed system in order to provide more stable devices and services? It seems unlikely at this point, however, that Apple and Google will merge, and become “AppleGoo” as Schmidt joked in 2007.