Persistent cookies vs. Session cookies
Cookies may be classified as session cookies or persistent cookies. Session cookies are erased when the user ends the Internet session, while persistent cookies remain on the user’s computer for some predetermined period of time.
OMB Memorandum 00-13 establishes guidelines for cookie usage at Federal web sites. … OMB clarified this policy, however, to allow the use of session cookies since these retain information only during a single session and do not collect information in ways that raise privacy concerns.