An acronym for Common Gateway Interface. CGI refers to programs that are used to produce on-the-fly content for browser delivery. Common CGI programming languages include Perl, C, and PHP.
 

CGI-BIN

One of the most common name for a directory on a web server that contains CGI files. These directories are often under heavier access controls than standard directories.
 

Click through

When a user selects a hyper text (web page) link. The Click refers to the noise a input mouse makes when a button is depressed. The through refers to the act of going "through" the link.
Many web statistics are kept on click-throughs (sometimes abbreviated as Click-Thru). Some advertising systems are based on paying sites when someone actually Clicks-Thru to a new site.
 

Client

When one program is designed to be the director or action computer in a two or more computer communiction. The computer that responds to the client is called a server. A browser is a Client, and a web server is a server
 

Cloaking

Using some system to hide code content from a user, and deliver custom content to a search engine spider. The word Cloak comes from Star Trek where the Klingons were capable of "cloaking" their ships invisible.
 

Combined Log file

A log file format that collects all the data in the Common Log File format, plus the information found in the referrer and user agent fields. Often includes separate scripting error logs as well..
 

Clustering

Some search engines Cluster pages from the same website in groups to keep any one site from dominating the top results. A poor mans directory service
 

Cold Fusion

A cgi database program from Allaire. Cold fusion uses a file extension of cf or cfm. Also used by some cloaking programs..
 

Common Log file

The standard log file format developed by the NCSA. The data contained in a Common Log File is limited by its lack of referrer and user agent information..
 

Counter

A counter counts hits or page views to a web site. Counter quality and featuers can vary widely. Most common are image tag counters that are activated when anyone views a page with graphics enabled..
 

CPA

Cost Per Action. The website only gets paid for advertising if the user purchases something at the advertisers site..
 

CPC

Cost Per Click. Search engine such as Goto.com charge sites for the number of users they send them on a per click basis..
 

CPM

Cost Per Thousand (think metric where M=T). CPM advertising models are based upon advertisers purchasing page views in blocks of 1000. If a website displays 7000 page views with banners, the site has just shown 7 blocks. If they are receiving $8 cpm, then they just made $56..
 

Crawler

A type of a A HREF="#spider">Spider that will download multiple pages from the same web site. Crawling refers to the fact, that the spider will look for links in the pages it downloads and then walk or crawl down through a web site.
 

CSS Cascading Style Sheets

CSS is used to add simple display styles to web pages. Of the 3 major browsers, Opera is probably the most compliant and has won several CSS awards (http://www.opera.com)...