The battle for Syria is raging on the ground but also on social media, where people on both sides of the conflict are hacking, posting and spamming in a frenzied propaganda war.

The Twitter feeds of news organisations have been hacked by pro-regime elements, videos purporting to show atrocities in Syria are regularly posted to YouTube and pro- or anti-government messages often flood Facebook pages.

"People are using all these social media platforms to influence audiences outside their country to support them; they're getting quite aggressive with it," said David Bailey, an expert on social media and the military.

"The so-called Arab Spring was very softly-softly. Nobody was being too harsh on the web against the regime... Now it's 'look at this, look at that, and I'll drag up as much nastiness as possible in the hope that you're going to support me.'"

Social media are widely credited for having helped mobilise and coordinate protesters during the Arab Spring, which kicked off in Tunisia at the end of 2010 and spread to Egypt, Libya and other countries.

In Syria, they are being used as a platform to galvanise public opinion as the nearly 17-month-long uprising against President Bashar al-Assad's rule rages on.

"It's not at all surprising that all the different elements in this conflict are making use of social media," said John Bassett, a cyber security expert at the Royal United Services Institute and a former British intelligence officer.

"It's the great arena where information struggles of whatever kind happen these days."

Pro-regime supporters, for instance, have spammed Facebook accounts deemed anti-Assad with thousands of vitriolic messages.

They are also posting pro-regime comments and "liking" them thousands of times -- a move that brings visibility to the statements.

In addition, the Syrian government is using social media to track activists, says Okhin, a Paris-based hacker who has worked remotely with people in the country to educate them on cyber-security.

"By infiltrating social networks using traditional techniques -- pretending to be another person, putting people at ease -- they gain access to (the activist's) list of friends, and can see who they're speaking to," he said.

The hacker, who refuses to reveal his real name, adds that the government has reportedly tortured some activists to gain access to their social media accounts.

The regime also use techniques such as phishing, he said.

"They put in place a fake Facebook page, and people log on via the Syrian Internet with their user names and passwords, which the government then recover and use."

The Twitter accounts of news organisations have also been hacked. Last weekend, for instance, people gained access to one of Reuters' feeds and posted tweets -- some of which carried false reports about rebel casualties.

But Bassett said these methods were still relatively crude.

"They're able to use many of these fora only because the people they are hijacking have poor IT security... And there's not a great deal of understanding in human psychology and human behaviour in what's being done."

Opposition activists, meanwhile, are also making use of social networks to raise awareness of the situation, mainly by posting grisly videos purporting to show people killed or maimed by regime forces, including kids.

But the videos are hard to authenticate, and this method has sometimes backfired, with other footage posted online allegedly showing rebels themselves committing atrocities.

"Neither side has ultimate control on the message going out," said Bailey.

In some instances, social media have allowed outsiders to get wind of significant developments on the ground.

One man claiming to be a rebel, for instance, on Tuesday posted a photo on Facebook of himself posing with a weapon identified by one intelligence expert as a portable surface-to-air missile launcher with infrared guidance.

If the account and photo are genuine, it would be one of the first indications that Syrian rebels have acquired anti-aircraft missiles.

But aside from those fighting each other in and out of Syria, other activists are also using social media to collate information about casualties and victims of sexual violence in the uprising.

A group of US-based activists has created Syria Tracker, a crowd-sourced effort where people on the ground can report crimes via direct web entry, email or by tweeting with the hashtag #basharcrimes.

By also tracking news stories, blogs, Facebook posts, and cross-checking the information with trusted sources and other reporting outlets, the activists have created a map charting deaths across Syria.

Women Under Siege Syria is another similar, crowd-sourced map that charts rapes during the conflict.

Ultimately, though, experts say there is little evidence the war of words on social media is having a measurable impact on the ground.

"It's not at all clear whether information operations on any side -- and certainly on the regime side -- are being that productive," said Bassett.