According to The Economist, the word awesome began its life in the Bible to describe someone feeling awe, usually by the omnipotence of God; times, however, have changed, and now the word has been watered down to the point where just about anything that is worthy has become just awesome.

From the article:

Soon the word needed no definition. "Awesome" became the default descriptor for anything good. In 1982, I was seven and I swallowed it whole. It stayed with me for decades. In 2005, I remember meeting a girl when I had just seen "Batman Begins", the moody psychological picture that reinvigorated a tired franchise. "It's awesome," I told her. "Awesome. Just awesome." She wondered, she later said, what kind of journalist had just one adjective in his vocabulary. Somehow, she married me all the same.