Gabriel Weimann of Haifa University said Facebook has become a source of intelligence gathering for Lebanon's militant Hezbollah group, he told Israeli news agency Arutz Sheva.
"Many users don't even bother finding out who they are confirming as 'friend' and to whom they are providing access to a large amount of information," he said.
In turn, he pointed out that terrorists create false profiles of themselves.
Weimann said "the most advanced of Western communication technology is, paradoxically, what the terror organizations are now using to fight the West," citing last week's cyber attack on thousands of Israeli credit card holders.
Shurat HaDin, the Israeli Law Center, has warned Twitter to stop providing communications access to groups like Hezbollah, or face a lawsuit based on violation of U.S. anti-terrorism laws, the newspaper said Monday.