DBoS stands for "Distributed Boycot of Services". The word DBoS was first used on twitter after Operation PayPal (#opPayPal), launched by the hacking (activism) collective 'Anonymous'. They asked everyone to boycot PayPal and close their existing accounts. According to some sources tens of thousands of people closed their accounts within hours. eBay stocks plummeted more than 2%, vaporizing some 1 billion dollars of shares, within the first 20 minutes after the NASDAQ opened. Some people claim it's due to #opPayPal.