Yeah, but "Buddhism" in the US means Soto and (especially) Rinzai Zen, since the Beats (esp. at the San Francisco Zen Center) did so much to popularize it. Otherwise, Buddhism has mostly stayed in local ethnic enclaves.
Insight meditation, a.k.a. "vipassana", has made big strides, thanks to Insight Meditation Society in Massachusetts and Spirit Rock in California, as well as S.N. Goenka's centers around the country.
Regarding Zen, koans are a feature of Rinzai, whereas Soto centers on just sitting.
