I have discussed the matter with few scholars because I myself was very confused on this subject (sharing views on an online forum with both genders) and how does Islam address this Issue. I even left forums for sometime to first clear my understanding on this issue.
C'mon man....loosen up a little...you don't have to sound pious and profound all the time.
The original poster asked a simple and earthly question - "Can a girl and guy just be friends ?".
And you say --- "Only Allah knows".......while such answers sound impressive and is sure to provide you the applause you are seeking.........this answer does not make any sense in logical terms. So, please loosen up and don't play to the gallery.