1. Certain words used can give probabilites of whether the author is male or female or what their native tongue is.
2. Coding practices can help determine who wrote a portion of a malicious program.
Dr. Krawetz presented at Black Hat. In his own words:
You are What You Type: No Classical Computer Forensics
by Dr. Neal Krawetz
My talk, "You Are What You Type", covers some of my research on anti-anonymity technologies. I'll show you techniques for telling if two documents are likely written by the same person, how to better guess gender and nationality, and even how to determine physical attributes like left/right handed, if someone is sitting too close to the monitor, and where their mouse is located. I'm including many real examples that cover the gambit from spammers and phishers to computer viruses and online dating.
Find his web site here:
Get the presentation from Black Hat:
http://www.blackhat.com/presentations/b ... rawetz.pdf
Read an interview with Dr. Krawetz:
http://www.infoworld.com/article/06/08/ ... ain_1.html