Access Service Provider (ASP) : An ISP that provides any kind of access to the Internet such as Cable
ASCII : American Standard Code for Information Interchange, it's basically "plain text."
CGI (Common Gateway Interface) : A protocol for gathering data from a Form and sending it to a program or Script such as Perl. Often used to indicate the entire method for processing a Form but in fact it is only a transfer interface.
Cookie : A note that a server leaves on your web browser so that it can remember what you looked at the last time you visited and customize your screen when you visit next. Cookies normally don't pose a security risk and are a must for some online browsing but could be used by the unscrupulous to glean information such as your websurfing habits. They are stored in a special folder on your hard drive aptly named cookies.
CSS (Cascading Style Sheets) : The expanded term is probably worse than the abbreviation. It refers to the ability to assign styles to elements on a web page (HTML document). Examples include position, size, color etc.
CTR Click-Through Rate (for Banner Ads) : The number of people that click a link compared to how many times the link is displayed.
Dialup Service Provider : An ISP that provides telephone connection services so that you can connect to the Internet with your modem. Can you say AOL?
Domain : An Internet Web Site identified with an IP address.
Domain Name : The name of a Web Site that is mapped to an IP address using a URL.
Drag-and-Drop : A GUI that allows you to use your mouse to drag elements from one location to another.
Form : HTML code to collect information from a visitor.