The popular micro-blogging site Twitter went offline this afternoon after a malicious cyber-attack on its systems, the company said.
Twitter was down for more than two hours before engineers at the California firm were able to get it back online with a warning at the website that 'we are continuing to defend against and recover from this attack'.
A post on the Twitter blog by co-founder Biz Stone said that Twitter was the victim of a denial of service attack, a technique in which hackers overwhelm a web site's servers with communications requests.
Twitter, which lets users publish short, 140-character messages to groups of online 'followers', is one of the fastest-growing Internet companies.
The number of worldwide unique visitors to the Twitter website reached 44.5 million in June, up 15-fold year-over-year, according to recent figures.
