PHP Session and SMF Question

[yo2lux]

I have a forum (SMF 1.1.4 + ApolloBB theme). I open this forum at:
www.mydomain.com

After page is loaded I see this in address bar:
www.mydomain.com/index.php?PHPSESSID=cdcd840642e7865c8f79e962ab79cc48;www

Why SMF put this PHPSESSID thing in URL ? I never see this message before.
Any idea ? Thanks!

[H]

The PHP session ID is used for session tracking. If the user has cookies enabled (and most people do) it should disappear after a few pageviews. If it doesn't then there is probably a problem with your php configuration