How did popular buddhism compare with original buddhist teachings?

I am assuming that what you are asking is how does Buddhism today compare to what the Buddha taught. Buddhism over the years has been enriched by each culture that has been exposed to; changing the nature of practice just slightly each time. So Chan Buddhism (China) is slightly different in practice then is Zen Buddhism (Japan, Korea). But the teachings have always remained the same. Now when I speak of practice, it is the methods used to teach the Dharma (the teachings). The biggest change in Buddhism since the Buddha is the development of Mahayana Buddhism. Mahayana Buddhism, which added teachings from later Buddhas and Bodhisattvas to The Buddha's original teachings in regards to living a compassionate life to help all other beings. So Buddhism adapts the methods but never the message or teachings.