This was not as sophisticated as the Turkish DNS attack earlier this month that redirected hundreds of sites (not all Israeli) that was seen as a "test run."
The confusion was caused due to the fact that the Palestinian sites, which have a .ps web suffix, use Israeli web servers.
"The hackers left anti-Israel messages on 70 Palestinian sites," said Shai Blitzblau, the head of Maglan-Computer Warfare and Network Intelligence Labs. "Most of them discovered it when it was already too late. Only after they broke in and sabotaged the websites did they found out these were Palestinian sites."
The message, which featured an image of an Israeli soldier washing blood off of his hands, read: "Because you voted on behalf of Israel on Blue (Mavi) Marmara report… We will suspend this site. You will apologize Netanyahu, you will apologize Israel."
Web site defacement is sort of like spraying graffiti on the front door of a company. It looks bad but doesn't really affect anything.
A DNS attack makes it difficult or impossible for customers to reach the company altogether.