Every time you visit a web page, you hand over a significant amount of information to the webserver about yourself. Depending on the way the site has been set up, this information may be thrown away, used to direct (or misdirect!) you around the site, or stored in evidence to use against you. This script just echoes some of the more intelligible values back to you.
According to the variable HTTP_REFERER, you accessed to this page from <none>. If this is blank, most probably you either entered the address of this script directly in your browser, or you are sitting behind a firewall or proxy server that stripped the variable from your http request. This may cause you problems with sites that check that HTTP_REFERER matches the site you are browsing.
According to the variable HTTP_USER_AGENT, you are reading this using version 1.0 of CCBot. This variable also provides information about the operating system and so on: the variable in full is CCBot/1.0 (+http://www.commoncrawl.org/bot.html). If you are using a 'minority' browser and find that some sites say 'go away, we only like Internet Explorer', this is how they do it. (Don't ask me why they do it...). In some browsers, you can change the value of this variable, to make the server think you have a different browser. There is some debate as to whether this is a good idea, or even legal!
The variable HTTP_ACCEPT_LANGUAGE is currently set to en-us,en;q=0.5. It probably says en for 'English', or maybe en-us for American English. Not all browsers set this variable, and not all sites use it, but it can be used to direct you to the right linguistic version of a website. If there is more than one option, the site will opt for the first one it can do.
Of course if you are in a cybercafe in Slovakia and don't speak Slovakian, this functionality may not appear especially useful, but you can usually reconfigure your browser so that you get directed to the site in English, and the next poor customer cannot see the site in Slovakian...
This is the potentially most scary one! The The variable REMOTE_ADDR is currently set to 38.107.179.234. This number is your IP address, which identifies you while you are connected to the Internet. If you have a static IP address (common with faster connections such as ADSL or with networks, anyone can trace this number back to your machine. If you have a dynamic IP address, as is normally the case with dial-up connections, you get a different IP address every time. But, before you head off to write rude things in everyone's guestbooks, the IP address can be traced to your ISP, and most ISPs are relatively easily persuaded to look in their logs to see who had a particular IP address at any particular time. All of which is to say that you are not as anonymous on the Internet as you thought...