Twitter has suggested it will consider legal action against the teenage creator of a virus that attacked the site four times over the Easter weekend.
Michael Mooney, 17, from New York, created the worm which first attacked the site in the early hours of Saturday.
Users spread the virus by clicking on an infected page. Their "tweets" then sent out messages to other users promoting Mooney's website StalkDaily.com.
The teenager has been quoted as saying he created the worm "out of boredom". He told Associated Press, "I usually like to find vulnerabilities within websites and try not to cause too much damage."
He also said he created the worm to expose the vulnerability of the microblogging site, which has seen user growth of 3,000% in a year.
Twitter co-founder Biz Stone said in a blog post that no personal information had been compromised because of the attacks. Around 10,000 posts were deleted on the site to prevent the worm spreading further.
He added, "The worm introduced to Twitter this weekend was similar to the famous Samy worm which spread across the popular MySpace social-networking site a while back. At that time, MySpace filed a lawsuit against the virus creator which resulted in a felony charge and sentencing. Twitter takes security very seriously and we will be following up on all fronts."
Twitter said it would conduct a review of what had happened, and said, "Every time we battle an attack, we evaluate our web coding practices to learn how we can do better to prevent them in the future."