My vote is to keep it as communication. I think the skill type (i.e., reading, writing, listening, and speaking - along with many other nonverbal, socio-cultural-historical aspects) will depend in large part on the type of MOOC and the way in which the MOOC is delivered by the facilitators. A more specific skill-type analysis might be helpful as a course needs analysis, but again, since a large part of MOOCs that I've seen have been asynchronous (focusing mainly on reading, writing, and some listening skills), language learners have the advantage of recasting, revising, repeating, etc. that is not possible in a live (synchronous) class. But again, this will depend on how much of the MOOK is asynchronous versus synchronous and which skills learners are required to use.
On the side of keeping the item as communication
I should add that this will facilitate comparison with Rita Kop's research on PLENK2010 -- if we introduce a material change, we loose the basis for comparison.
An extra thought to consider as we work towards consensus.