So really it seems that little OERs are a way of giving structure to all the online chat, blogging, posting and sharing of resources that go on. For me in my FE college context that seems like a manageable step, whereas big OERs would be quite a major innovation.
Martin Weller suggests that little OERs, the long tail of the online resources, encourage engagement and outreach, as well as increasing openness and the reuse of resources. All of these are desirable.
He also wonders about potential clashes of loyalty and responsibility if something we distribute as an OER (e.g. a blog) offends our employer. That's one to ponder!