How should I create a question for my persuasive speech?

Hi, I am in high school doing a persuasive speech. The topic that I feel most passionately about and one that I believe is controversial in today's society is the usage of social networking sites (e.g. Facebook, Myspace, Twitter). I want to do something regarding the privacy issues on social networking sites. For my speech, I must have a clear opinion (FOR/AGAINST).

For example, I thought of one (I don't want to do this specific topic because I feel that I will not be able to write a lot about it):
"Social networking website should be more secure."

^It needs to be in a format like that, "_____ should be ____." I also need to support it with three good reasons.

I need a topic about these social networking sites that is especially controversial and/or debate-able. Most importantly, I need to be able to extensively research about whatever topic I am doing.

Thank you.