Broken friendships produce the bitterest feuds, which explains the big beef between Steve Jobs' Apple and Bono's Elevation Partners. Now Elevation is investing in Pandora, the beloved internet radio site edging ever closer to competition with Apple.

Elevation's forthcoming investment, which TechCrunch sources peg at around $100 million, may be the best warning yet that Apple and Pandora are on a collision course. The streaming radio service has a symbiotic relationship with Apple at the moment, sending 25 percent of its music to iPhone owners, praising the company's business strategy and even spurring new features in the iPhone operating system, which was recently modified to allow audio apps like Pandora to run in the background.

But in December, Apple acquired a streaming music service of its own, and the business press immediately called the move a response to Apple facing "competition from other providers like Pandora." Given that Apple's iTunes not long ago added a "genius" feature that recommends music like Pandora does, it wouldn't be a surprise if the company's forthcoming revamping of Lala gave Pandora new (and well-funded) competition with some of its features.

And let's not forget the rivalry between Elevation and Apple. Elevation was co-founded by Jobs' buddy Bono and has since helped drive a wedge in the two men's friendship: Elevation was a big investor in Palm, which briefly turned itself into a sort of Anti-Apple staffed largely by Jobs refugees collaborating on a would-be iPhone killer known as the Pre; Jobs was reportedly outraged at Palm for raiding his company for employees. Elevation co-founder and managing director Fred Anderson, meanwhile, entered a high-profile dispute with Jobs, for whom Anderson once worked as Apple CFO, over who was responsible for an options backdating scandal at Apple. Jobs' board fingered Anderson, while Anderson said he was hung out to dry.

Of course, it's possible Pandora and Apple are in for a lifetime of friendly cooperation — and that Elevation has patched things up with Apple and is investing in Pandora strictly because it knows a promising company when it sees one. Hopefully that's the case, because Apple does not always play fair with its rivals on the iPhone.

If Apple and Elevation, and Jobs and Bono, are finally ready to bury the hatchet, they can take some inspiration from the pro-peace anthem penned by an Irish poet, who lamented, "The battle's just begun / There's many lost, but tell me who has won? / The trench is dug within our hearts / And mother's, children, brothers, sisters torn apart. How long / How long must we sing this song?"

[Pic: Jobs and Bono at a 2004 event to promote an Apple iPod model tied to an African AIDS charity. Getty Images.]