Google shares have topped $1,000 (£617) for the first time, jumping 13.8% on Friday after the company reported better-than-expected earnings.

Shares in the online giant closed 122 points up at $1,011.4, and have risen 42% since the start of 2013.

Friday's share price rise followed the company posting a 36% jump in net profits to $2.97bn for the July-to-September period on Thursday.

Google's revenues also beat forecasts with a 12% rise year-on-year.

"We are closing in on our goal of a beautiful, simple, and intuitive experience regardless of your device," Google's chief Larry Page said in a conference call with analysts.

Analysis Look at a graph of Google's share price and you'll see a mountain range with two prominent peaks - one back in 2007 when it climbed above $700, another today as it breaks through $1000. When it floated in 2004, early scepticism about the search giant's real value was quickly dissipated, as investors marvelled at the fast growing earnings from its advertising formula. Then, from 2007 the shares halved in value as doubts surfaced about whether the growth story could continue. But, over the last four years, as Google has shown that it can be as big a force in mobile advertising as it has been on the desktop, confidence returned sending the shares ever higher. And 18 months after Facebook floated, its story is looking rather similar. Facebook shares, which halved in value in the months after its stock market listing, reached a new high today - and again it's the social network's proven ability to make money from mobile advertising which has restored confidence. Two companies battling for the upper hand in a vast new industry - but right now investors are betting that both can deliver spectacular growth.

The strong earnings report also helped other online companies, with Facebook shares adding 4.4% to a new high of more than $55. Amazon rose 3.4%.

Google's market value is about $334bn, which is still well below Apple's $461bn.

Google was floated in August 2004 at $85 a share, giving the company a market value at the time of $23bn.

The company reported its quarterly earnings on Thursday after US markets had closed.

Google said that paid-for clicks increased by a quarter during the July-to-September period, from a year earlier, the highest rate of growth in the past year.

This offset an 8% fall in average cost-per-click, the price advertisers pay Google when consumers click on their ads.

"We view solid paid clicks growth to be a good indicator of demand, driven by the continued shift to mobile," JP Morgan analysts said in a note.

Video ads

Several brokers have raised their share price target for Google on the back of the company's new initiatives to attract advertisers.

In February, the company launched a service to help advertisers market through a mix of smartphones, tablets and desktop computers. And analysts believe there is still significant potential to generate revenues from its video-streaming website YouTube.

YouTube-branded video-ads surged more than 75% in the quarter from a year earlier, with 40% of traffic now coming from mobile devices.

"We estimate that Google's key YouTube asset generated approximately $4bn in revenue in 2012, positioning Google extremely well for the strong growth in video advertising," RBC Capital Markets analysts wrote in a note.

Analysts at Jefferies said Google is best positioned to benefit from mobile devices with one billion activations of its Android system. Google sells applications and content through its Google Play store.