How many of the things you "know" do you have memorized?
Do you remember how to spell all of those words you let the spellcheck catch? Do you remember what fraction of a teaspoon of salt goes into that one recipe, or would you look at the list of ingredients to be sure? Do you remember what kinds of plastic they recycle in your neighborhood, or do you delegate that task to a list attached with a magnet to the fridge?
If I asked you what day of the month it is today, would you know, or would you look at your watch/computer clock/the posting date of this post?
Before I lost my Palm Pilot, I called it my "external brain". It didn't really fit the description; with no Internet access, it mostly held my contact list, class schedule, and grocery list. And a knockoff of Minesweeper. Still, in a real enough sense, it remembered things for me.The vast arena of knowledge at our fingertips in the era of constant computing has, ironically, brought it farther away. It seems nearer: after all, now, if you are curious about Zanzibar, Wikipedia is a few keystrokes away. Before the Internet, you'd probably have been looking at a trip to the library and a while wrestling with the card catalog; and that would be if you lived in an affluent, literate society. If you didn't, good luck knowing Zanzibar exists in the first place!
But if you were an illiterate random peasant farmer in some historical venue, and you needed to know the growing season of taro or barley or insert-your-favorite-staple-crop-here, Wikipedia would have been superfluous: you would already know it. It would be unlikely that you would find a song lyrics website of any use, because all of the songs you'd care about would be ones you really knew, in the sense of having heard them sung by real people who could clarify the words on request, as opposed to the "I think I heard half of this on the radio at the dentist's office last month" sense.
Everything you would need to know would be important enough to warrant - and keep - a spot in your memory.
So in a sense, propositional knowledge is being gradually supplanted by the procedural. You need only know how to find information, to be able to use it after a trivial delay. This requires some snippet of propositional data - to find a song lyric, you need a long enough string that you won't turn up 99% noise when you try to Google it! - but mostly, it's a skill, not a fact, that you need to act like you knew the fact.
It's not clear to me whether this means that we should be alarmed and seek to hone our factual memories... or whether we should devote our attention to honing our Google-fu, as our minds gradually become server-side operations.