Tim Berners-Lee saw the possibility of using hyperlinks to link any information to any other information over the Internet. Hyperlinks were therefore integral to the creation of the World Wide Web. Web pages are written in the hypertext mark-up system HTML.
Links are specified in HTML using the <a> (anchor) elements. To see the HTML used to create a page, most browsers offer a “view page source” option. The HTML code consists of tags; the hyperlink tag starts with “<a”, and includes a reference “href=”URL”>”, marking the start of the link. The text between the hyperlink tag and its corresponding “closing” tag ( “</a>”) is called the anchor text.
Webgraph is a graph, formed from web pages as vertices and hyperlinks, as directed edges.
http://en.wikipedia.org/wiki/Hyperlink