Glossary - E

EPC
Earnings Per Click. A unit of measure used to determine a site's ability to convert visitors into customers. Calculated by dividing total sales amount by total page views .

EPV
Earnings Per Visitor . A unit of measure used to determine a site's ability to convert visitors into customers. Calculated by dividing total sales amount by total number of visitors to the site.

everflux
Once a month Google updates its entire index of web sites. That is called the Google Dance and can last for a couple of days – usually it's from about the 20th to the 28th of every month. Around June/July 2002 we started seeing something else though. Google results started changing all through the month, in between the major updates. This continuous change became known as everflux. It happens because Google, in an ongoing effort to make their results as relevant as possible, has introduced a “fresh crawl” that runs each day. The idea behind the fresh crawl is to update pages that change regularly. This allows Google to serve results that are up-to-date with current events.

exact match
If not for partial matching , fuzzy matching , collaborative filtering and stemming , search engines would only return exact matches. A search for "power" would only return documents containing the exact term, not documents containing variations or related terms like powerful, strength etc.