The New York Times has an interesting article detailing Apple's once friendly but now tenuous relationship with Google. The two companies have worked together in the past, and Google CEO Eric Schmidt even served on Apple's board of directors. In fact, Google founders Larry Page and Sergey Brin apparently considered Steve Jobs a mentor and would visit him at Apple's offices often. There might've been a little bromance, too; Brin and Jobs are said to have taken long walks together in the Santa Cruz foothills.
But Jobs hasn't been happy with Google's entry into the cell phone world, and he reportedly threatened to sue Google should it implement multi-touch on Android-based devices. Multi-touch is now available on several Android phones, including Google's own Nexus One. However, Apple hasn't filed suit against Google directly. Instead, it's gone after handset maker HTC, which just happens to manufacture the Nexus One, among other Android devices.
Apple's contentious relationship with Google may be strained even further if iPad alternatives embrace Android or perhaps even Google's Chrome OS. Given the markedly different mindsets that seem to be steering the two companies, further conflict seems inevitable. The Times' article is loaded with other interesting tidbits and is well worth reading.