Below is a glossary of the terms used within this section. Some entries are adapted from those provided by WebTrends Software,whose product is used to generate the user statistics for EEMS. However the opinions expressed are our own.

Term	Explanation
Hit	A single action on the Web server as it appears in the log file. A visitor downloading a single file is logged as a single hit, while a visitor requesting a Web page including two images registers as three hits on the server; one hit is the request for the .html page, and two additional hits are requests for the downloaded image files. While the volume of hits is an indicator of Web server traffic, it is not an accurate reflection of how many pages are being looked at.
Orders	Publications orders from the library have been monitored since January 2002. These give an indication of the effectiveness of the library service in meeting user needs for information. These orders only cover requests for hard-copy publications; many of the brochures in the library can be downloaded as Word or Adobe Acrobat documents.
User sessions	This is measured as the number of visits to the site each month. A user making a repeat visit within the same month would be counted twice. However, some users may view the site off-line or through a service such as AOL which keeps a dedicated cache of popular sites on its own servers. This may lead to their activity not being recorded. User sessions are a good measure of a site's success, since the measure combines repeat visitors (who presumably find the site useful) with once-only visitors, typically referred by a search engine.
Unique visitors	The number of individual users who access the site. Repeat visits from the same computer are assumed to be the same user and count as one visitor. The measure is important in answering the question 'how many people visited this site?' for which user sessions would be an incorrect measure. However, when comparing different sites this measure does not distinguish between one that meets the needs of a regular group of users and another which may attract one-off interest but does not generate repeat visits.