I think that this is very concerning. After reading this I will be more careful about what I write in my e-mails. Not that I am a spy but we all need privacy and this is way too unethical. I also hope that other big companies do not commit such acts. People and companies like Yahoo need to have more regulations about ethical issues. Now we can see that fiction books like Digital Fortress are not fiction anymore. Most probably they are real and cases like this reduces our trust to governments.