Backlinks - are incoming links to a web page. Backlinks are also known as incoming links, inbound links, inlinks, and inward links.
Hyperlinks - clickable link in text or an image on a web page that takes you to another location within the same document, web page, web site or to a completely different location.
Link Popularity - refers to the total number of inbound links to a particular web site by different search engines such as Google, MSN, Yahoo etc.
Nofollow - is an HTML attribute value used to instruct some search engines that a hyperlink should not influence the link target's ranking in the search engine's index. It is intended to reduce the effectiveness of certain types of search engine spam, thereby improving the quality of search engine results and preventing spamdexing from occurring.
Outbound links - these are links that direct the Internet user to another website links, to another pages
PageRank - see PR
PR - PageRank, a Google patented method for measuring page importance or relevance; ranges from 0 to 10, 10 being the best. PageRank is a “vote”, by all the other pages on the Web, about how important a page is. A link to a page counts as a vote of support. The more votes that are cast for a page, the more important the page must be. PageRank of the page that is casting the vote is very important. Higher PageRank of voter page means better PageRank for voted page. For more details see Introduction to Google PageRank.
Spamdexing - (also known as search spam or search engine spam) involves a number of methods, such as repeating unrelated phrases, to manipulate the relevancy or prominence of resources indexed by a search engine, in a manner inconsistent with the purpose of the indexing system
Spoofing - impersonating another person or computer, usually by providing a false email name, URL or IP address.