In the field of biological weapons, there is almost no prospect of detecting a pathogen until it has been used in an attack.
Smallpox, which spreads by respiration and kills roughly one in three of those infected, took hundreds of millions of lives during a recorded history dating to Pharaonic Egypt. The last case was in 1978, and the disease was declared eradicated on May 8, 1980.
Pakistan has dozens of laboratories and production and storage sites scattered across the country. After developing warheads with highly enriched uranium, it has more recently tried to do the same with more-powerful and compact plutonium.
Suppose a bad guy guesses the password for your throwaway Yahoo address. Now he goes to major banking and commerce sites and looks for an account registered to that email address. When he finds one, he clicks the 'forgot my password' button and a new one is sent - to your compromised email account. Now he's in a position to do you serious harm.
Everyone and his Big Brother wants to log your browsing habits, the better to build a profile of who you are and how you live your life - online and off. Search engine companies offer a benefit in return: more relevant search results. The more they know about you, the better they can tailor information to your needs.