Salaamalaykum waa rahmatullahi,
I think this is a wake up call for most of us that our posts on TTI and other web forums can be traced , recorded and then reproduced by media outlets or individual authors. Now imagine how the law enforcement agencies will be tracking what we post on here...
As for sister Harb, if it is true that you are part of various forums that are mentioned in that book, then you are putting yourself under suspicion.
Threads such as this one
http://www.turntoislam.com/forum/showthread.php?t=71857 isn't helping things much either. A thread or two like these in a forum watched by law enforcement agencies can put you in a lot of trouble. (Plus the views expressed there are not in line with Islam either).
If I were to advice you, I would tell you to concentrate on basics of the deen as you are a revert and try to advance your knowledge as much as you can. This is what is advised by the scholars of Islam to new muslims who aren't raised in a muslim environment (or family) and have to invest a great amount of time to converse themselves with various teachings and beliefs of Islam and how they need to be applied in one's life.
Though I am not suggesting that you show indifference to what is happening in Palestine, I am rather suggesting that you reduce your fervor and direct it into a more rewarding and beneficial activity some of which is obligatory on every muslim such as being able to recite the quran, learning proper aqeedah, knowledge of obligatory (and jurisprudence concerning it) and prohibited actions etc etc.
Posting multiple threads on various forums is not going to help the cause of Palestinians in any manner other than getting an emotional response from other members. There is hardly anyone of us who is unaware of the atrocities happening in Palestine, May Allah azz zawajal assist and help them Ameen. It is important for us muslims to make dua for all the muslims suffering from oppression and hardship all over the world including palestine and gaza, which is a great act of support in itself.
Also, at times people who just occupy their time with such issues are devoid of knowledge of Islam from authentic sources (from the knowledgeable scholars) and are misled by ignorant and ill informed muslims, who partake in activities that are unIslamic and cause harm and no good by harming innocent humans, and end up giving Islam a bad name.
Wasalaamalaykum waa rahmatullahi