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[edit] Overview
A
web session is the period of time between when a
web site user authenticates her/his identity and when the web server decides to stop remembering that the authentication has taken place (typically leading to a "your session has timed out" message). This is done for a number of reasons, primarily security; many web sites are overzealous about their implementation, however, e.g. timing out a shopping cart session when no personal information has been entered yet, or timing out an
online banking session when the user has been busily downloading check images the whole time.
[edit] Commentary