If you're concerned about who is watching you online you might want to try Collusion - an experimental add-on for the Firefox Internet browser - it visualises who is tracking you online.Download and listen to an interview with Mozilla’s Mark Surman.

If you're interested in online privacy look out for a new Tactical Tech project we're launching in April called Me and my Shadow – an interactive website to help advocates understand how online data can be used to trace their activities.