Trust Rank Algorithm is all about to combat the web spam. Web Spam denotes those web pages that are the result of spamming.
Any deliberate action solely in order to boost a web page's position in search engine results, incommensurate with page's real value is called spamming.

Web Spam Taxonomy contains:
a) Boosting Techniques
b) Hiding Techniques

Boosting Technique of spamming further divided into:
(i) Term spamming
(ii) Link spamming
Term spamming - Manipulating the text of web pages in order to appear relevant to queries. The target are for term spamming are Body of web page, Title, URL, HTML Meta tags, Anchor text.

Term Spamming:
- Repetition of one or a few specific terms e.g., free, cheap, Viagra.Goal is to subvert TF.IDF ranking schemes - Dumping of a large number of unrelated terms e.g., copy entire dictionaries
- Weaving Copy legitimate pages and insert spam terms at random positions
- Phrase Stitching Glue together sentences and phrases from different sources

Link spamming - Creating link structures that boost page rank or hubs and authorities scores. There are three kinds of web pages from a spammer's point of view

1. Inaccessible pages
2. Accessible pages e.g., web log comments pages spammer can post links to his pages