Too many lines of the discussion to respond to now... but here's a try.
Verina had a relevant point on the difference of discussing the ephemeral to material/immaterial. Yet this is a boundary zone which I'd like to return to.
And here we could get some help from Wendy Chun:
"What we must analyze, as we try to grasp a present that is always degenerating, is the ways in which ephemerality is made to endure."
I've had the privilege to attend her lecture on "the enduring ephemeral" a couple of times now.
Even though I can't say I have a total grasp of her argument, it basically deals with the conflation of storage and memory in von Neumann's cybernetic interpretation of the function of memory. If memory can essentially be seen as a re- and de-generative process - in digital computing, memory came to be made enduring, localized in a place of lasting storage. What is really exciting about Chun's argument is that she talks about how this principle come to guide how we for example look upon the internet as an archive, blinding us to precisely the ephemeral of media.
In this sense, I have to disagree with Jon Ebner writing in a previous post: "I don't think (New) Media works are really ephemeral." Maybe the point is rather not to consider whether certain media forms are ephemeral or not (animation, new media, film etc) but rather be attentive to how the ephemeral is a basic constituent of the continuing degeneration of the present - made to endure in documentation, which then itself goes on to be ephemeral.
(recalling not only Chun but also the Bergson quote on the pastness of the present in Elena Cologni's recent post)