Doesn't plagiarism usually entail the unauthorized passing off of another's work as one's own for pecuniary or material benefit? In this case, if the blogger in question gives its usage the old retroactive thumbs-up, how is it different than Ronald Reagan or JFK taking credit for the oratorical creations of Peggy Noonan or Ted Sorensen, respectively? Or, more to the point, the retelling of a joke one hears from a third party? Bloggers, like speechwriters, are crafting their work for a larger audience, and not only expect that our ideas are going to get ripped off by others higher up the food chain, we need that to happen to feel like we're making a difference.