Sean (iii) contributes a world-view that is very different from my own but that is in fact more appropriate to a Poul Anderson Appreciation blog! (I think I can safely say that we would both like to see more world-views expressed here.)
Sean (iv) not only introduced me to the works of S.M. Stirling but also showed me that Stirling is a worthy colleague and successor of Poul Anderson. Thus, it has become appropriate to discuss several of Mr. Stirling's works on Poul Anderson Appreciation and in fact I still await the arrival by post of Nantucket Volume II.
Thus, Sean's contributions have significantly influenced both the content and the direction of the blog.