The 10Gbps speed, which is twice the speed of USB 3.0, is simultaneous in both directions. It also has the potential to scale to 100Gbps in the next 10 years. In other words, this isn't vaporware; Intel has demonstrated the technology twice before.
If past reports are true, Apple could be among the first to incorporate the technology. It's long been whispered that it was actually Apple that conceived the idea for Light Peak, and the company reportedly helped Intel guide the development of the standard. Interestingly, Apple recently used Intel as an excuse for not supporting USB 3.0 (SuperSpeed). We speculated that Intel was delaying support for SuperSpeed on purpose, due to Light Peak.