What Are Plogs, And Should We Care?

What is a plog? Seems the term is currently being claimed by at least five groups:

It could get nasty agreeing on what a plog is. And I notice that Amazon are trademarking the term, so they’re not going to be too happy with other people stealing their name, even if they might not have been the first one there. I personally think they should win, since ‘plog’ sounds very similar to ‘plug’ which is clearly what Amazon is trying to do with their products.