I think I'm fairly confident in saying that CR and certainly Mr and Mrs McCann know who the main contributors are on twitter and on the few forums that remain that are hostile to them. I think if they were considering libel against these people then they would have done so by now. However I am certainly not suggesting that I believe they have ruled it out.
I think the whole trolling issue is one which is desperately sad, unnecessary and tremendously hurtful.
While upsetting I think they have probably considered it as more than an irritant than actually interfering with their search for Madeleine. Although the endless stream of organised petitions, FOIs and obstruction (eg campaign to flood Crime Watch TV programmes broadcast to help Madeleine) in my opinion could only have been designed to do so ... else what was their purpose?
What has been humanly possible to help Madeleine has been and continues to be done by the appropriate agencies now investigating her case, the Policia Judiciaria and Scotland Yard, enabling the McCanns and their Private Detectives to take a back seat.
Perhaps they have now decided that enough is enough. Who would blame them?