It's sad how rare authoritative, free resources are on the web. It's cliche to say how incredible an opportunity the Internet presents to share the world's knowledge, but the most valuable knowledge, the serious scholarship, is effectively withheld from the public. Imagine how some debates would change if more authoritative resources were easily accessible (I don't want to exaggerate the value of 'authority', but it's a much better starting point than Wikipedia) and cited with a link, such as in HN discussions. Partly as a result the Internet is mostly rumor and popular notions, not knowledge.

I've even turned to SEP for mathematical concepts (to the extent it covers math), for example, because there is no free authoritative resource in that field.