It has been called the 'fifth dimension of warfare'. Along with land, sea, air and space - the cyberworld is increasingly becoming a new frontline.Innovations in technology are changing the tactics of modern-day conflict. There are new tools in today's arsenal of weapons. Helped by advances in electro-magnetics and modern information and communications technology, a new form of electronic warfare has been created. It is called cyberwar and is increasingly recognised by governments and the military as posing a potentially grave threat.And it is not just cyberwar that is a growing phenomenon. The internet has empowered cyberactivism, allowing people to share information and mobilise support to take direct action - both online and on the streets.Social networking sites such as Facebook, Twitter and YouTube have been at the forefront of this new wave of cyberactivism, helping to galvanise the protests that have recently spread across the Arab world.The so-called Arab Spring has been described as an electronic revolution. Protesters were turned into citizen journalists - taking frontline images on their mobile phones and uploading them via their computers for the world to see. The regimes may have jammed the signals of satellite news channels and banned international reporters from entering their country, but they were unable to prevent citizens from becoming reporters in their own right.From cyberactivism to cyberwarUsing the internet as a platform for political action is one thing. But infiltrating and disrupting computer networks and databases takes cyberwar to another level. American security experts have warned that a cyber-attack could cripple key governmental and financial systems and it is a threat the US is taking seriously.In recent years a cyberwar has been brewing between China and the US, with both countries accusing each other of running an 'army of hackers'.A key battlefield in this war has been the case of Google. The US internet company partially withdrew from China in 2010 after a tussle with the government over censorship and government-backed hacking. China accuses the US of using Google to spy on the country, while Google accuses China of hacking into the email accounts of some of its members.The US also appears to be engaged in a cyberwar with another erstwhile enemy: Iran. It appeared to begin in 2009 following Iranian anti-government protests - sparked by the disputed presidential elections which saw Mahmoud Ahmadinejad win another term in office.Seeking to deprive the opposition of its main means of mobilising the masses, the Iranian authorities sought to choke off internet access.But the protestors continued to use sites such as YouTube and Twitter and when Twitter planned some routine maintenance that would have taken it offline for a few hours, Hillary Clinton, the US secretary of state, asked the site to stay up and running while the protests continued.