But in some ways the problem of spam on social networks is more intrinsic than that. The sites' core function is to bring more people together and to share their opinions. The social networks make it easy to join and easy to share content. In fact, the URL (unique resource locator) shorteners that have sprung up to further ease sharing on social networks have been a boon to spammers because they create multiple links to the same page while concealing the domain name.
Spammers have created an account -- and Judge cited estimates that as many as 30 percent of Facebook accounts are fakes that belong to spammers -- they can buy a Twitter follower for 2 cents, a Facebook friend for 3 cents or a "like" for 4 cents. Facebook accounts are also not infrequently hacked, allowing the spammer to fabricate a public recommendation of his product from the account holder.
According to Chris Grier, a computer scientist at the University of California at Berkeley who researches spam on social networks, the number of social spammers continues to grow, suggesting that they are making money.
The new cohort of spammers is not yet established enough to run their operations on botnets, said Grier. But security companies have seen some botnets repurposed to run this kind of spam. Malware is relatively rare, largely because the social networks take more aggressive action against it than they do commercial spam.
Experts say social networking sites are already getting more serious about spam. Facebook recently announced a partnership with several security companies that would give users access to free antivirus software for six months. And Twitter recently brought legal action against commercial spammers on its platform.
The evolution is a familiar one. Web email providers like Hotmail were initially hostile to security companies' overtures to help with spam, said Wisniewski of Sophos. But when the problem began to hurt their bottom line, they began working opening up to the companies. He expects Facebook and Twitter will act more and more aggressively against spam if it begins to drive users away.
But Grier offered the flip side of the comparison to email spam.
"As the defenses get better, we'll see more sophisticated tools. We'll see the same sort of evolution on social networks" that we did on email.
Which means users could be in for a long ride.
Cameron Scott covers search, web services and privacy for The IDG News Service. Follow Cameron on Twitter at CScott_IDG.