My understanding about all this is that if you are purchasing digital stuff (or services) on eBay from an international seller, you *may* be charged 10% GST on the purchase *if* you are an Australian consumer.  An "Australian consumer" is one that is *not* registered for GST.  Apparently, if you are registered for GST this new "netflix" tax does not apply.

This page from the ATO may help:

https://www.ato.gov.au/Business/International-tax-for-business/In-detail/Doing-business-in-Australia...

... as for the bit in the email about GST on eBay fees - that doesn't seem to have anything to do with this Netflix tax and is just completely confusing.

I'm guessing they have sent this email out to all australian eBay sellers because they have an ABN and are potentially registered for GST.  The link in the email that allows you to "registered for an exemption" seems to be related to exempting us (as buyers) from GST charged on things we buy overseas *IF* we are registered for GST.

I may have this completely wrong, but that's what I thinking it is about!