open-source vs proprietary security software

[Karol Pietrzak]

hello.
i'm trying to explain (if not convert) to my friend why open-
source security software is better than proprietary and am 
trying to develop concrete and specific evidence.  i know the 
standard arguments for and against, but i need more.  for 
concrete examples, i have the resignation of phil zimmermann and 
the recent choice of nai not to release full source code of pgp. 
 anyone have any other ideas?

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noodlez:   Karol Pietrzak
GPG/PGP-KeyID: 0x3A1446A0