Well, one way is to ask bloggers who appear to be parroting pro-goverment propaganda without any thought the following question:
Has the American, Israeli and/or any other government directly or indirectly instructed or requested that you write supporting any of their actions, policies or positions, or helped to organize or in any way supported you in making any writings?This is a very helpful question.
Well, they will respond yes, assuming that they are an honest person writing in response to one of the governments' calls for pro-government blogging.
Indeed, Air Force regulations require that the blogger identify themselves as military.
So - right off the bat - some people will honestly identify themselves if you ask.
Moreover, routinely asking this question will help educate others on the Internet about the U.S. and Israeli propaganda campaigns, so that they can weigh blogs and comments in a rational manner with an educated eye.