For Buddhists, the practice of yoga asanas as a method of mindfulness practice is especially meaningful. Although some traditional yoga teachers emphasize mindfulness of breathing in synchronization with the breath, the Buddhist context of using bare attention to penetrate the moment as a means to realization is not as emphasized or is missing. During Chan and Vipassana practice, especially on retreats, slowing down all activity to the point that you can peer into its very nature is essential and can lead to a very direct experience of impermanence and self-nature. This understanding and emphasis coupled with the practice of yoga asanas is particularly useful.
In the Yoga Sutras, there is the concept of uninterrupted, moment-to-moment one pointedness or focus. But the goal there is not realization of self-nature in the Buddhist sense, but realization of individual self (atman) as distinct from the citta vrittis. Of course, this is where Buddhism departs, with an emphasis on there not being an independently existing person, self, or soul.
Practicing yoga has been a kind of experiment for me. Can a practicing Buddhist practice yoga in such a way that the fundamental truths of Buddhism, suffering, impermanence, and no self (anatma), are not distorted or lost? I think the answer is definitely yes, but it requires a clear understanding of the differences in addition to the similarities of the two traditions. Otherwise, it becomes a confusing melting pot that doesn't do justice to either tradition. For me, the goal is not Patanjali's dualistic realization of individual self as distinct from phenomena and Universal Self (Purusha of Isvara). It's also not Shankara's non-dualistic realization that self is Brahman. Rather, it's the complete liberation from attachment to any notion of self. Once self is removed from the picture, perception is pure and everything is seen just as it is. This is true, unimpeded and boundless liberation. When the experience of self is lost, perception pivots on itself and myriad things sing in harmony with all other things, infinitely correlated, perfect and complete. Any clinging to "self" collapses this perfect harmony, the natural state of things, to self and other, internal and external, interesting and uninteresting, good and bad, mine and not mine.
One might say that one who experiences "aham Brahmasmi" (I am Brahman) also experiences this same non-dualistic reality and is not impeded by attachment or aversion to anything since everything is experienced as Self. Yet Buddha's awakening specifically had the characteristic of going beyond an eternal notion of self, even Universal Self, as the highest enlightenment. According to Buddhist sutras, as long as there is any identification with self, one is still trapped in the cycle of birth and death and not completely liberated. The wisdom of knowing the truths of suffering, impermanence, and no self engenders compassion for all sentient beings and frees one to act completely for the benefit of others, without regard to self. I've seen this selflessness in my Shifu, Chan Master Sheng Yen and in my Vipassana master, Ven. Chanmyay Sayadaw. They both have the quality of being completely present and available, fully there for you with no distraction, when you talk with them. Your ego could even get puffed up with the feeling that you were the most important person in the world to them at that particular moment. But, they also had the compassionate ability to deflate the ego when the time was right. I've noticed the same quality in the Dharma heirs of Master Sheng Yen and some of Chanmyay Sayadaw's disciples and lay students -- fully present, awake and clear, penetrating, insightful, patient, and compassionate. I noticed the same qualities in the Dalai Lama. The world needs more saints like these!
For Buddhists and non-Buddhists, practicing yogasanas with mindfulness can be very beneficial in developing a very direct perception, a bare awareness of space, time, motion and sensation. Deepening this experiences enables the silence of meditation to stabilize in daily activity and bring about moment-to-moment penetrating focus along with awareness unbound by the environment. The union of Buddhist understanding with mindful practice of yogasanas is particularly beneficial. I'm very glad to hear of courses being taught, such as those at Spirit Rock, that have this focus. This is bound to improve the overall landscape of Yoga as it is taught in the West.