"The arrest of the suspects hits online scammers hard, " said Alibaba.com boss Jonathan Lu.

BBC: China arrests 36 for fraud on Alibaba and other sites

Far more common--but still damaging--are the high-volume crime spikes, spam e-mail distribution and "phishing, " a pernicious technique for stealing credit-card information. (For more on online scams, check out "Where The Scammers Are".) The carnage is hard to pin down in dollar terms, but Marcus Ranum, chief security officer of Tenable Security, says it's "billions upon billions"--far more than all "major" hacking incidents combined.

FORBES: Magazine Article

Last year there were more than 5, 600 complaints of romance scams in which scammers targeted individuals who search for companionship or romance online.

FORBES: Where Americans Lost Money Online