The number of Twitter accounts suspended for suspected criminal activity started to rise again during 2010, security company Barracuda Networks has reported.
The company's annual look at 'the dark side of Twitter' plots a gently rising graph of suspensions as criminals returned to target the service and its users after a major cull in late 2009.
According to Barracuda, the average suspension rate was around two per cent of accounts in the second half of 2010, a rise of 20 per cent on the first half of the year. However, the graph also plots some alarming spikes that don't show up in averages, including one in mid-year that reached above five per cent for a period of days.
Twitter, it appears, succeeded in beating back the massive surge in criminality that hit the service in October 2009 and has now settled into a war of attrition that puts the emphasis on rapid detection of misbehaving and bogus account that try to spread spam and malware.
A live feed of suspected Twitter spam accounts as analysed by Anubis Networks can be found here.
In other areas, while Twitter is making progress against its 'dead zone' - legitimate twitter accounts that show low activity levels - the service is still rather like a noisy conversation in the corner of a large and otherwise silent room.
According to Barracuda, 43 per cent of the service's user base are now 'true' users, which is to say that they have more than 10 followers, have made at least that number of tweets and follow at least that number of people.
On this calculation that still leaves a huge swathe of the service's user base that is barely active, with around 11 per cent of accounts having no followers at all.
The survey offered some better news for Google, which is no longer the undisputed 'king of malware' distribution in searches as it was last summer. Google's drop from 69 per cent of malware in June 201 to 38 per cent today shows that criminals have now diversified to other engines, with Yahoo now at 30 per cent, Bing at 24 per cent, and twitter itself on eight per cent.
Overall, around 1 in 1,000 search results leads to malware, with the term 'music+video' the most likely to return a problem link.