The attack on CafePress follows a DDoS attack on web host Crystaltech on Cyber Monday, which has been heavily promoted by online retailers as the kickoff of the online shopping season. DDoS attacks are often timed to peak traffic periods when uptime is critical.

Industries conducting large volumes of transactions are frequent targets for a cottage industry of digital extortionists using distributed denial of service (DDoS) attacks. These attacks typically are preceded by a request for payment from parties who claim the ability to “prevent” an imminent attack. If no payment is made, a DDoS attack follows. Cafe Press did not indicate whether it had received a request for payment, or had any indication of the attackers’ motives.

CafePress.com is an online marketplace that lets users create, buy and sell customized merchandise online using the company’s print-on-demand and e-commerce services. The site says it has more than 2.5 million members who have created over 35 million products.