In a recent Supreme Court ruling, Israel has ruled that anonymity on the Internet can only be forcefully removed "where a cause of action against the anonymous commenter exists and where the anonymity was used in order to avoid liability[.]" This means that simply prosecuting a case of Internet slander no longer gives the prosecution a right to uncover the identity of the defendant.
In a similar case back in August 2009, Canadian model Liskula Cohen was attacked by an anonymous blogger in a blog called "Skanks in NY" and requested that Google revealed the identity of the blogger. The US Supreme Court ruled in favor of the prosecution and ordered Google to release the relevant information, uncovering the anonymous poster to be 29-year old fashion student Rosemary Port. While Port was simply asked to cease to defamatory blogging, she went on the offensive, suing Google for $15 million for not protecting her rights to the proper extent.
In the Israeli case in question, Israeli healthcare practitioner Rami Mor sued an Israeli ISP to give up the identity of the blogger defaming him. The motion was dismissed, and the case went to the Supreme Court of Israel. They ruled that the blogger was entitled to his anonymity unless certain criteria of malice were met.
While the ruling is controversial in and of itself, the fact that the Israeli government currently has no judicial process in place to order ISPs to give up identities is causing the ruling to be even more ground-breaking than it already is. Since there is no process to reveal identities, any motion to reveal identities of Internet users will be dropped until a legislative process is worked out.
This effectively grants unconditional anonymity to anyone on the Israeli Internet until the government can come up with a legal procedure to force ISPs to release the information requested.
Details of the proceedings and rulings can be found (in Hebrew - but Google translates it well) here.