The Central Intelligence Agency on Tuesday declassified six World War I-era documents -- the oldest classified documents held by the spy agency -- containing the ingredients used to create invisible ink.

The formulas, which date from 1917 and 1918 and were the CIA's oldest classified documents, were apparently so sensitive that as late as 1976 the agency decided against releasing the information.

Samsung Electronics said Tuesday it would take counter-action against Apple after the U.S. firm filed suit alleging that the South Korean giant copied its smartphones and tablet computers.

Apple's lawsuit claims Samsung's mobile phones and Galaxy Tab imitated the iPhone and the iPad.

Charging electric cars at night eases a smog problem caused by fossil-fuel plants which provide the power for these vehicles, researchers reported on Tuesday.

Plug-in cars are viewed as a key tool in the fight for a cleaner planet as they do not emit tailpipe pollution when they run on electricity.

Twitter is in "advanced talks" to buy TweetDeck, a popular platform for accessing the service, for some $50 million, The Wall Street Journal reported Monday.

Asked about the report, Twitter said: "We don't comment on rumors. We don't provide off-the-record background on rumors. We don't wink twice or release puffs of smoke abt rumors."

Taiwanese smartphone maker HTC has risen to global prominence by transforming itself from a contract maker into a viable brand, one of the toughest feats in the fiercely competitive hi-tech industry.

"Quietly Brilliant" is the motto adorning HTC's advertisements -- and quietly, brilliantly it has managed to grow and grow, until recently it stunned the industry by becoming as big as Nokia.

Google paid tribute to Charlie Chaplin on Friday by transforming the celebrated logo on its homepage into a silent movie.

When clicked, the logo, known as the "Google doodle," plays a silent film featuring members of the doodle team acting out Chaplin-esque sketches.

The blue-hulled vessel would slip by unnoticed on most seas if not for the white kite, high above her prow, towing her to what its creators hope will be a bright, wind-efficient future.

The enormous kite, which looks like a paraglider, works in tandem with the ship's engines, cutting back on fuel consumption, costs, and carbon footprint.

New Zealand passed a law against online piracy Thursday which outlaws file-sharing and threatens repeat offenders with having their Internet access cut off.

The new law allows for penalties of up to NZ$15,000 ($12,000) to be paid to the copyright owner and if this is ineffective offenders can have their Internet account suspended for up to six months.

A handful of Greenpeace activists was outside Facebook headquarters on Wednesday, calling on the social network to "unfriend" coal energy for powering data centers and other operations.

Members of the international environmental group set up a large computer screen to display comments streaming in from around the world in response to a Facebook post urging the firm to join an energy revolution.

The head of Google's search evaluation team shakes his head dismissively at the idea of anyone thinking the firm's winning Internet-sifting formula is completed.

Far from it.