And now Google faces the most lethal threat of all: Microsoft , aroused, is taking aim at the popular site.

FORBES: All Eyes on Google

AIDS, now a lethal threat to increasing numbers of South Africans.

ECONOMIST: Merging the first and third worlds

And now Google faces the most lethal threat of all: Microsoft (nasdaq: MSFT - news - people ), aroused, is taking aim at the popular site.

FORBES: All Eyes on Google

He was not arrested because under Florida law the use of lethal force is allowed if a person feels seriously under threat.

BBC: Florida judge sets George Zimmerman bail at $150,000

Red squirrels are under threat from non-native greys which carry a virus which is lethal to reds.

BBC: Highland boost to red squirrels

Obama announced new "presidential policy guidelines" last week on the standards his administration has been using when deciding to launch lethal strikes, including a guideline to strike a target only if it presents an "imminent threat" to U.S. national security and only if the target cannot be captured.

NPR: Drone Strike Comes Despite Transparency Pledge

In a major policy speech Thursday, President Barack Obama raised the bar for U.S. lethal action against terrorist groups, saying the U.S. will strike only at those who pose an imminent threat to Americans, rather than at terrorists who threaten U.S. allies and interests.

WSJ: Militants, Chased From Mali, Pose New Threats