> the Australian court will say that the US court has no jurisdiction in Australia

One would hope that'd be a given and go without saying.

> The Australian court could conceivably force the EFF to change how its site is shown to people in Australia

Not without jurisdiction over the EFF they can't.

> Then after realizing that people in Australia can still access the US version of the EFF's site, force the EFF to change its site in all countries.

Not without jurisdiction over the EFF they can't.