PS - And for those who do like explanation better than surprise: the link above will take you to a somewhat wikipedia-like knowledge base of yogic-related information. I just found it a little while ago, so can't speak to the overall quality - but the bit of info I saw, seemed very good - and very comprehensive.
Please Note: This is NOT a "Consumer-Yogi Friendly" site - this is more for those who like to flip through the Vijnanabhairava Tantra or the Devi Mahatmya Stotram, for fun (and yes, it's in English. Pretty much. )