| 1. | Cache | a space storage of saving some webpages or files in order to preventing from being generated again unecessarily |
| 2. | Click-Through | clicking on a link, usually an advertisement, to visit a web vendor. |
| 3. | Click-Through-Rate (CTR) | the number of times a link is clicked on divided by the number of impressions. |
| 4. | Cloaking | - serving one version of a page to a human visitor and a different version to the search engines. The cloaked version usually contains a list of targeted keyword unintelligible to humans. Presently considered unacceptable by most major search engines. |
| 5. | Clustering | The process of listing only 1 or 2 pages from a website within the search engine results. |
| 6. | Content | - in this regard, the text of a web page, visible or not, examined by search robots. |
| 7. | Cookie | peice of data stored on a user's computer by a website in order to get the sufers' information |
| 8. | Counter | a small software application (written in perl, php etc) that counts the number of hits, unique visitors, and/or page views that a web page receives |
| 9. | Crawler | nowadays, synonymous with robot |
| 10. | Cross Linking | Having multiple websites linking to each other. |