Last week, the UK's House of Lords Select Committee on Communications released a report on "social media and criminal offences." Britain has faced a number of high-profile cases of online harassment this year, which has prompted demands for new laws, and better enforcement of existing laws.

"Our starting point," the peers begin, "is that what is not an offence off-line should not be an offence online". The report is cautious in its recommendations for modifying existing regulation, and reasonable in spelling out how current criminal law can deal with patterns of harassment and bullying, whether they intersect with modern social media or not.

The report does gave tentative support, however, to removing online speakers' ability to communicate online without recording their identity. The report's authors write:

From our perspective in the United Kingdom, if the behaviour which is currently criminal is to remain criminal and also capable of prosecution, we consider that it would be proportionate to require the operators of websites first to establish the identity of people opening accounts but that it is also proportionate to allow people thereafter to use websites using pseudonyms or anonymously. There is little point in criminalising certain behaviour and at the same time legitimately making that same behaviour impossible to detect. We recognise that this is a difficult question, especially as it relates to jurisdiction and enforcement.

This presents a false dichotomy. The use of anonymity and pseudonymity tools online don't render ordinary police detection impossible. The solution offered by the House of Lords (demanding the identity of online users be recorded at the online service registration) won't make anonymous commenters disappear from the Net either. The experience of countries like South Korea and China has shown that determined speakers will use fake identities — and that requiring online service providers to collect troves of identification documents increases the risk of identity theft.

What requiring identity papers whenever you join a new social media site, however, would do is criminalize the actions of anyone who has a legitimate need to remain anonymous. Those groups include abused spouses and other harassed individuals, whistleblowers, political speakers and others concerned with retribution from above. Some harassers use anonymity tools; but all anonymous speakers need them. The negative effects of harassment will continue but the benefits of anonymity will become tied to a criminal offense.

While unsure whether its new proposal to mandate compulsory identity registration on all online websites might be workable, the peers make another suggestion based on current UK law. Websites might be incentivized to prohibit anonymous discussion, they suggest, by the provisions of the UK's new libel law. Websites under the law are protected from defamation lawsuits aimed at third-party postings. They lose that protection if they do not reveal the posters' identity, and don't comply with a "notice-and-takedown"-style set of regulations.

The idea that the incentives of existing law might be used to chase anonymity out of the public arena even when it is not, by itself, illegal, is worrying. Despite the Lords' suggestion, British law doesn't seem to reach that far — but Europe's courts might.

Late last year, the European Court of Human Rights (ECHR) decided, in Delfi vs. Estonia, that European websites were liable for anonymous comments even if they took down content. In the Delfi case, the court said that an Estonian news site was liable for third-party comments because their take-down procedures did not go far enough to ensure "sufficient protection for the rights of third persons", that should have anticipated that a particular news article was controversial, and that the comments section was anonymous. The Delfi decision has been appealed, and the ECHR's Grand Chamber is currently considering the case. But Delfi and the Lords' report shows courts and policymakers continue to respond to pressure to put limits on anonymous speech, even when an explicit law banning anonymity is beyond the pale.