I agree with you that a blog is something like a Frankenstein character, that you don’t have complete control over your blog. Your RSS feed goes places you cannot control (including RSS scrapers, content thiefs and sploggers) and posts may be put in a different context outside your blog. The same goes for people referencing your blog or receiving trackbacks (if you have enabled automatic trackback ).

I like your reference to the mirror and the portrait except that in this case the people who look at the portrait leave their marks. They can add a bit to the portrait in the form of a comment or you can see their shadow when they are passing by in the recent visitor plugins.

It is true however, like you pointed out, that there is some vitality of information needed to sustain a blog after the blogger has quit. And that a blog can not survive without its blogger. But can we say that Death of the blogger = Death of the blog?
I still want to emphasize the character that the blogger creates. The blog then becoming another entity that is not directly linked to the blogger, but something that is perhaps in a way self-sustaining. A Frankenstein-ish character, patched together by plug-ins. Once the blog is created it is perhaps out of the hands of the blogger? In this light it would be interesting to see the blog as self-sustaining. In this light our old http://mastersofmedia.wordpress.com blog would be an interesting case :)

The blogger of course does retain a rigid form of control, having the ability of the killswitch (delete blog) to kill it off in a case of emergency?

I think we do both perhaps see the blog as an autonomous entity once it is created. It becomes a characteristic mirror to the blogger, and a portrait of the blogger for the audience. But like a mirror and a portrait, both the surface of a mirror and the photograph are autonomous beings. But in what way does a blog form character.

I believe we’re back to the subject of your thesis now ;)

When I say a blog can live without it’s readers I do not mean to imply that readers don’t matter. They are one of the most important aspects of blogs and the relationship you establish with your readers might vitalize the blog or the blogger. I mean this in the sense of “you can live without friends, but what kind of life is that?” A blog can have no readers and continue to be “fed” by its “master” thus staying alive. Although it is hard to imagine a blog without a single (page)view these days.

The blog that stays alive after the blogger has died (in the figural or literal sense of the word) captures the vitality of the blog after it has been raised by its master.

Data that stays alive after the subject has passed away: Etoy – Mission Eternity