What is the current legal status of Bitcoin around the world? Has there been any concrete information about the legality of Bitcoin in any country?

Since any information can be injected into the blockchain, then if child porn / copyrighted material is injected into the blockchain, does this make Bitcoin clients illegal in some sense?
At this point, the legality of bitcoin remains largely untested. To date, there have been no legal actions brought against any bitcoin exchanges (which would likely be the first place for the legality of bitcoin to be tested, rather than end users) and multiple bitcoin exchanges are seeking legal clarification regarding the jurisdictions they are operating in.

Some non-profits including the EFF have chosen not to accept bitcoin at this point in time because of untested legal issues.