By launching "Operation Israel", the hacktivist collective called on hacker groups and individuals to participate and launch cyber attacks as a means of protest against Israel's occupation of Gaza, their human rights violations, and to show solidarity with newly recognized Palestinian state.
The Hackers Post has a list of participating hackers, and according to reports and claims by the groups, a series of websites have been hacked and defaced, and data from them stolen and leaked online.
The attacks started with hits on government sites, but later turned to hundreds of private and business sites hosted on .il domains (Hacker News Bulletin has a list of them that they keep updating).
Anonymous has issued a list of its own, cataloguing successful hits and pastebins with stolen info.
Among the most prominent targets were the websites of the Central Bureau of Statistics, Israel Defense Forces, Israel Ministries of Defense and Environment, the official website for the Israeli Prime Minister, and so on.
Israel prepared itself by shoring up defenses and setting up a hotline for ordinary citizens to call in case they experience problems.
Anonymous claims that over 100,000 websites, 40,000 Facebook pages, 5,000 twitter and 30,000 Israeli bank accounts have been compromised, and that the damage reached $3 billion.
Israeli sources say the numbers are inflated beyond measure. Professor Yitzhak ben Israel, head of the National Council for Research and Development, said that the damage is "more or less non-existent," and that "Anonymous doesn't have the ability, nor is it its aim to destroy the country's essential infrastructure," adding that the real goal was to bring the world's attention to the conflict between Israel and Palestine.
A lot of the allegedly stolen data has apparently been leaked in the months before OpIsrael, but has now been changed to make it seem that it came from Israeli websites.
Israeli hackers have not been standing by idly. According to Israel Today, they managed to hack opisrael.com and change the front page to include pro-Israel statements.
Finally, INN reports that Jordanian security forces have arrested several individuals who are thought to have been involved in the attacks, and RT says that several Palestinian activists were arrested in Gaza. According to Gaza Hackers Team sources, three of them are hackers.