RFD: Request for Discussion -- Curl Class

PHP Curl, client url library class, this function takes url and return it to plain text what' s this? How? . this morning activity browsing brought me to an interesting example of using curl package using PHP 5, to read this example howto you will need to know some basic of object - oriented programming. I'm not yet testing the code for myself how to use it, actually it goes to my curious to find out what curl is and what it can do,the php.net curl is the answer.
I have got to do some learn again 'bout this since it really new. so please help me by giving this post comments or examples.