Becoming part of the conversation... literally.

Under Secretary of State for Public Diplomacy Tara Sonenshine's latest speech on Public Diplomacy and Counterterrorism mentioned projects in which the U.S. government are activelly engaging in discussions on Al-Qaeda online forums. This is an attempt to get the "other side of the message" out. According to Sonenshine, the logic behind this approach is this:

"By targeting the hardliners, we are really trying to reach the middle grounders, the fence sitters, the sympathizers and passive supporters."

That seems plausible if it weren't for this - if someone has gone through the trouble of finding said forums and engaging there, they are probably past the point of being "fence sitters", and it would be, arguably, far more unlikely that adding a different perspective would change their hearts and minds.

What is the actual success rate of approaching this kind of group, or rather, how can one measure whether opinions have changed? The U.S. government should focus on ordinary citizens - those, it seems to me, are actually far more likely to change their minds about terrorism and the way they perceive the United States. 

These online forums can be useful for intelligence gathering and pin-pointing actual members of terrorist organizations, but they just don't seem like the best place for conducting public diplomacy.