This week's attacks that crippled Twitter raise a number of questions.

The New York Times suggests the target was an economics professor from the republic of Georgia. According to the paper, the hackers used thousands of malware-infected computers to send junk traffic to his pages on Twitter, LiveJournal, YouTube and Facebook, basically disabling these services. In other words, the Russians were trying to stifle his criticism of their regime. That coincided with the first anniversary of last year's war, sparked by the tensions over the breakaway region of South Ossetia. The millions of Twitter and Facebook users around the world were just collateral damage.

That might be, but there are some worrying signs. As Ryan Singel writes in Wired, the alarming part is the attacks don't make sense and might be the work of a psychopath. And if that's the case, there is no point looking at a rational reason, like for example extortion.

There is another concern: the stability of the Twitter site. As the IT newsletter, The Register says, the attacks raise questions about Twitter's fragility.

As The Register says: "Twitter's reliance on just one service provider, and apparent lack of back up and redundancy, much less a comprehensive disaster recovery plan, goes a long way towards explaining why it was hit so badly."