Services

A browser lets you link to other resources on the Internet using different types of services. The most common ones are:

http: Uses the HyperText Transfer Protocol to access a World Wide Web server. For example: http://www.nasa.gov/ connects to the NASA home page.
gopher: Gopher is software which follows a simple protocol for tunneling through TCP/IP. It is a distributed document search and retrieval system based on a client/server model. It was invented at the University of Minnesota. For example: gopher://gopher.tc.umn.edu connects you to the Gopher at the University of Minnesota.
ftp: Uses the File Transfer Protocol to access an FTP Server. FTP is used to transfer files and it can be done anonymously. Versions of the File Transfer Protocol have been around since 1971. For example: ftp://ftp.fda.gov connects you to the FTP Server of the Food and Drug Administration.
mailto: This allows the reader to send electronic mail to the electronic mail address specified. It is often used with the <ADDRESS> tag to allow the reader to quickly send mail to the author of a document. For example: mailto:comments@www.hq.nasa.gov would send electronic mail to
comments@www.hq.nasa.gov
news: Uses the Network News Transport Protocol to access an NNTP (Usenet News) Server. It is the browser that determines which NNTP server to use. The format of the NEWS URL is different. For example: news:rec.humor allows the reader to access the newsgroup rec.humor.
telnet: The purpose of the Telnet protocol is to provide a fairly general, bi-directional, eight-bit byte oriented communications facility. Its primary goal is to allow a standard method of interfacing terminal devices and terminal-oriented processes to each other. It is mostly used to login to a host on the Internet. For example: telnet://cyber.gate.net will create a TELNET session for you to login on CyberGate, an Internet Service Provider.

I understand the services. What about the anchor tag?