It should be reverted back to 'normal' next week at least on a temporary basis. In the meantime, creating an account is simple, free, and will allow you to log in and use the wiki normally (and even set some custom features and edit pages too!) and you can select 'leave me logged in' so you'll only need to log in once unless you clear cookies. Plus this will allow you to edit pages.
Anon-access was turned off when the wiki went down two days in a row (and not the super-slow-agonizing-to-load-but-still-will-load-if-you're-patient sort of down, but just flat out inaccessible) and the second time took the entire webserver with it. This was a better solution than turning the wiki off completely, assuming it continues to prevent the malicious behavior that was killing our systems. We're hoping to update the wiki software this weekend and we will try allowing anon access again once that's completed.