The year was 1997. During a graduate school take-home exam in abstract algebra, one of my fellow students emailed the questions to AskDrMath.com and received answers before the exam was due.
Fast forward to 2005. One of my international graduate students showed me a website hosted in his home country (in a language not based on the Roman alphabet, therefore not easily searched by most westerners). Students post homework, exams, and solutions for many North American universities, indexed by class and professor.
I was happy to see that the Wall Street Journal wrote about these issues in their 9-April-2009 article “Do Study Sites Make the Grade?” by A.M. Chaker, pp. D1-D2.  If you aren’t aware, online study sites give students access to homeworks and exams posted by hundreds of thousands of registered users. They are the old sorority/fraternity files in the Internet age. According to the article, solutions to 225 textbooks are also now on the web. Furthermore, students post and answer questions from fellow users around the globe.
According to Chaker, arguments for such sites include: “With the Internet, the sites say, it’s inevitable that all this information will be available to students anyway. It’s up to the schools, they say, to come to terms with modern times. ‘We’re just putting things out in the open,’ says Koofers’ Mr. Rihani, who says his site is making old tests previously accessible only to fraternity members, available to more students. Mr. Rihani notes that putting old tests online can help force more professors to refresh their old exams periodically. The study sites are likely to propel schools to rethink the way they teach.”
When NYU’s Aswath Damodaran spoke in our Master Teacher Series on 24-April-2007, we learned that he writes every exam from scratch and posts all old exams with solutions on his website. I think there’s evidence in the above article that more folks should consider Damodaran’s model, or at least rethink the way we embrace the technology.
 If the link to the WSJ article does not give the full-text version, use this Google search instead.