Wow, this was quite hectic. My brother is in London at the moment and the fear isn't nice. I want to express sincere condolences to the affected families.

Bruce Schneier makes a plea for people to not do things like, this. Applying security randomly and only in the transit system is silly. Some proper thought needs to be put into it. If I were a terrorist all I need do is bomb a supermarket or the like, while everyone is running around bus and train stations. Security is only worsened by knee-jerk reaction.

Schneier says:

Smart counterterrorism focuses on the terrorists and their funding -- stopping plots regardless of their targets -- and emergency response that limits their damage.

I would argue one further, stop pursuing unethical murderous foreign policies that generate the animosity towards America and Britian in the first place. Stand up, apologise, and start acting like humanitarians and clean up the mess that has been created without even majority consent.

Side note: Wikipedia and Wikinews' coverage has been excellent. It is also far more impartial and less sickening than CNN's money making exercise complete with spiffy new 'London Terror' logo.