Several small Web startups have been hit recently by a wave of distributed denial of service, known as DDoS, attacks, in which attackers knock a victim offline using a flood of traffic and refuse to stop until their victims pay a ransom in bitcoins, The New York Times reported.


The amounts demanded are typically low - which seems like a lot of work for little payoff - but those who have been targeted say they think the nominal amounts are bait which could lead to future extortion demands. If a company is willing to pay $300, for example, it might be willing to pay $3,000 or $30,000 down the road.


Startups hit include Vimeo, a video-sharing company; Basecamp, a project management software company;, a link-shortening service; Shutterstock, a stock photography agency; MailChimp, a email marketing provider; and Meetup, a New York company that connects groups offline.


The FBI is looking into the attacks, according to two people close to the inquiry who spoke only on the condition of anonymity. They said the agency was operating under the assumption that the attacks were the work of the same culprit, or group of culprits. Jennifer Shearer, an FBI spokeswoman, declined to comment.


Last year, the frequency of DDoS attacks jumped eightfold from the previous year, and the size of the attacks eclipsed previous peaks by more than 200 percent, according to a report.