Gmail gives some tips for its users to use mail service efficiently. The tips link was lockated at the top right corner of you gmail account. go through it and know every thing of gmail.
Researchers from Harvard School of Engineering and Applied Sciences shown the first controlled flight of Robotic insects. They are half the size of a paper clip, weighing less than a tenth of a gram, the robot was inspired by the biology of a fly, with submillimeter-scale anatomy and two wafer-thin wings that flap almost invisibly 120 times per second.