The attackers who participate by loading these pages and going off to dinner, sleep, or on with their days open themselves up to attacks back through drive-by attacks. Imagine a simple scenario: the victims modify their sites to include some code like LuckySploit that commits a simple set of attacks. The attacker’s machine reloads the page (this is, after all, part of the attack). Hit a browser or accessory bug and bam, the attacker has been attacked. Now you’ve got a foothold on the attacker’s machine and, if you’re a sophisticated cyberwar player, you can use this to further understand your adversary. This is a dangerous strategy. If you’re going to employ this kind of attack you need to remember you may be putting your “army” at risk.
That's interesting because it has happened before. A similar type of campaign back in 1998 by EDT was focused on the Pentagon and the site under attack retaliated:
In September 1998, the Electronic Disturbance Theater, a group of activists that practices politically driven cyber civil-disobedience, launched an attack aimed at disabling a Pentagon Web site by flooding it with requests. The Pentagon responded by redirecting the requests to a Java applet programmed to issue a counteroffensive. The applet flooded the browsers used to launch the attack with graphics and messages, causing them to crash.
(Also, the defacers are getting into it: A gov.ir site was defaced too (http://www.marivan.gov.ir/Election.htm))
