On the one hand, we wouldn’t expect our daily interactions to be recorded and stored for long. Most of them, anyway – and certainly so for our most personal ones. On the other hand, the web is a medium where things tend to last a while, if not for very long thanks to efforts such as the Internet Archive’s. The delicacy of where to rest the equilibrium, I think, stems from the particularity of the web as a medium itself: a web page is kind of like ye olde book, but it adds the possibility of easy changes and user interactivity. In other words, if so used, a web will sit between traditional written media and face-to-face (or technologically mediated, but unrecorded) interaction.
Perhaps by custom, perhaps by nature, we expect personal interaction to be ephemeral, and we have no problem with other media, such as books, newspapers, etc., to store their contents for long. It’s no harm to publish a book with our thoughts and have it found across libraries in the world (indeed, it is a very nice thing), but we would feel violated if our conversations at home where recorded without proper cause.
The web stays somewhere in between. It’s a place for words to lie and last, but also for personal interaction. Personally, I favor ephemerality on the Internet, but don’t see it as characteristic of it. It’s not a given, and we should find a place for it, but only as far as personal interactions go. I want to be able to remove (or, at least, anonymize) whatever I post online in the manner of a casual conversation. But I want other kinds of content, such as manuals, news, etc., to be preserved from ephemerality.
I’m not sure whether The Internet Archive stands within these bounds. I would like to see it more as an opt-in facility for website administrators, instead of requiring manual forbidding.