No other mantra is so closely associated with Tibetan Buddhism. Om mani padme hum in at the heart of Vajrayana. The literal translation, Jewel in the Lotus of the Heart or Hail the jewel in the lotus, doesn’t begin to describe the powerful effect this mantra has on clearing negative karma. I speak from personal experience.
Om mani peme hung evokes Chenrezig, the Bodhisattva of Compassion also known as Avalokitesvara, Guan Yin (Kuan Yin), Padmapa-ni, and Lokes'vara. His Holiness the Dalai Lama and His Holiness the Karmapa are both said to be incarnations of Chenrezig.
I’ve been chanting Om mani padme hum for almost ten years now. The tattoo on my left arm is Om mani padme hum.
Om mani padme hum is the mantra inside Tibetan prayer wheels. While other sutras, mantras, etc. are used, multiple copies of Om mani padme hum are written on scrolls of paper rolled up inside. Spinning a prayer wheel spreads the beneficial effects of the mantra.
These six syllables are widely used by Tibetans and Tibetan Buddhists alike: on jewelry, carved on stones, on wall hangings, t-shirts, you name it. Many folks have tattoos of Om mani padme hum in both Tibetan and English. I do.
Read what the Dalai Lama’s piece on Om mani padme hum. The Foundation for the Preservation of Mahayana Tradition has a essay about it too.
Turning a prayer wheel is like repeating the mantra inside. The more it turns, the more powerful the effect. Turn your computer’s hard drive into a prayer wheel. Download this text file that contains 108 iterations of Om mani padme hum [ZIP file]. Save it to your hard drive. Now your hard drive is a prayer wheel. How fast does your hard drive spin? 5400 times a minute, 7200 times, more? The file is small enough to occupy one contiguous block on your unfragmented hard drive. No geek like a Buddhist geek, ehhh?