As I look more at the "Long Tail of Time" (see my first post on that here) in preparation for this Long Now talk, I'm finding that one of the biggest forces driving demand into the archives is Google. We're used to the newspaper model of content: new is what matters and yesterday's news is fish-wrap. But Google and the other search engines are time-agnostic [UPDATE--see below]. And the result of that is a dramatic shift in demand towards older material.
What matters to modern search engines is relevance, measure mostly by the number of other sites that link to a page. A little-noticed implication of this is that older content tends to score higher because it's had longer to accumulate incoming links. In other words, search inverts the usual priority of content: older is often better.
We don't think of Google as a time machine, but that's actually what it is. By subsuming time under more important criteria such as "authority", it frees us from the tyranny of the new. Quality lasts and freshness is just one factor in many that determine value.
I looked at my own server logs here at the thelongtail.com to quantify this. Search (mostly Google, but a bit of Yahoo and MSN) now accounts for 37% of my traffic, and most of that is to older posts rather than new posts or just the blog's home page. The picture looks like this:
In other words, without search, only 12% of my traffic would be to my older posts. With search, it's nearly 40%.
I'd wager there's not a newspaper in the world that shows that sort of archive-heavy distribution. Yet that turns out to be the natural shape of demand in an organic search-blog ecosystem. Which is to say it's increasingly the shape of the web itself. Archives Rule!
UPDATE: in the comments, Jim points out that time is indeed an important factor in Google's results. A very readable summary from its original search patent is here. But it's clearly not the only criteria and since the spider only gets to the average site once a week or so, the really new stuff (ie, the last day or two) doesn't even show up in regular search. (blog search and news search use different methodologies and do get newer content). The net effect of this--really new stuff absent, older stuff accumulating more links, and Google decaying relevance over time by some unknown amount--still amounts to a strong advantage for the archives. Exactly how strong we can't say, but based on the effect on incoming traffic alone (see above) it's significant.