Here's a handy list of useful vocabulary for the World Wide Web.
A special note is needed for http://www.shareware.com -- this is a search engine that looks for programs that you can download from the Internet. These programs are not commercial ones like Microsoft Word, but rather smaller programs that often do useful and interesting things. The MOO and Chat clients I've asked you to download you can find by using www.shareware.com and searching for "MOO" or "Chat."