According to this post, in Australia you cannot disclaim all warranties. The Ritchey Permissive License does ("The material is provided without warranties of any kind"), but it also states "You must be legally capable of being bound to all the requirements of this license". Would this prevent Australian's from accepting the license, or would portions of the license simply not be upheld in that jurisdiction?
First of all, a warranty is different from a guarantee under Australian Consumer Law (ACL). The license purports to exclude the former but not the latter. So, on a literal reading, the license doesn't offend the ACL and is probably fine on that basis alone although this may not be what the licensor intended.
Notwithstanding, even if "warranty" and "guarantee" are to be read interchangeably it is not clear that this would offend the ACL. Since this is a supply of services (not goods) there are only three guarantees in the ACL: Guarantee as to due care and skill (60), Guarantees as to fitness for a particular purpose etc. (61) and Guarantee as to reasonable time for supply (62).
It should be obvious, given the nature of the website, that 61 and 62 are not going to be applicable. So, this leaves only 60:
If a person supplies, in trade or commerce, services to a consumer, there is a guarantee that the services will be rendered with due care and skill.
Before this ACL guarantee is engaged there needs to be a consumer (which there is) and the supply must be "in trade or commerce". Trade or commerce is not defined in ACL except circularly in terms of geography:
"trade or commerce" means trade or commerce within Australia or between Australia and places outside Australia.
This is a deliberate choice by the legislature because s51(i) of the Constitution grants the Commonwealth legislative power "with respect to trade or commerce" and clearly legislation cannot define a term that is used in the Constitution (without definition) but it can narrow its definition for the purposes of the Act.
"Trade or commerce" is interpreted by the courts based on the totality of the circumstances. A supplier is "in trade or commerce" if they are routinely or regularly engaged in 'business' (for-profit or not-for-profit) and the particular supply forms part of that business. However, supplies that are 'personal' rather than 'business' in nature are not captured. Similarly, activities by a 'business' that are not "in trade or commerce" such as lobbying (unless their business is as a lobbyist) are excluded.
Note that the Act refers to "supply" - this includes supplies that are neither contracts and/or for which the consumer provides no consideration. For example, a supermarket giving free samples of a foodstuff is a "supply" "in trade or commerce" and is captured by the ACL.
With respect to this particular site, it appears to be a private blog and therefore the supply is not "in trade or commerce" so the ACL guarantees are not engaged.
Now, if you wanted to take something under this license, which requires you to use this license when you 'onsell' and you were doing so in the context of a "supply" "in trade or commerce" to a "consumer", you wouldn't be able to.
Basically it depends on whether there is a contract and whether the licensor is a business (vs private individual).
For Australian consumer law to apply, the "material" must be supplied "in trade or commerce".
That is, if you are supplied with the "material" outside of a trade or commerce (simply put, outside of a contract, but see DaleM's comment), Australian consumer law does not apply and so does not prevent you from accepting the license.
If there is a contract, whatever parts of the license are consistent with Australian law will be terms of the contract. The rest of the license will simply not apply.