See his follow-up for discussion of that and other issues:
http://woodgears.ca/toys/slinky2.html
You could even ask for donations with a "keep the slinky slinking" button, so you could pay for electricity and server.
Man, asking all the hard questions. It reminds me of the "If a tree falls in a forest and no one is around to hear it, does it make a sound?" question. Maybe you could live stream it though.
Also note that there are juggling machines that are stable without any active control [1]. Designing a self stabilizing slinky escalator could be really hard though (if not impossible).
Also, Hi Matthias! I'm a big fan of your YouTube videos, it's really great to see one make it to HN (even if it wasn't linked directly to you).