SUGGESTION Google Pange Rank- Why?

Why we are always depending on google page rank? Is there any other search engine provides page rank?
What is the importance of google page rank? I know every angle of blogs, forums, websites, articles and more are speaking about google page rank. Why?
The replies would be highly useful to all of us. Why can't we popularize a site for eforum page rank? Make some suggestions to decide page rank by eforum ? It is possible. But find some ways. Google a giant in the computer field. I accept. Why some other giants are not evolving to compete with google? This is my suggestion.
www.googlepagerank.com