Stumble(d) Upon An Incrediby Interesting Time Waster

Do you ever think about life prior to the Internet? So many of us rely on it so heavily, for so many things, that it's hard to imagine life without it.
As a writer and researcher, it's amazing to me to remember that at my first reporting job, I relied on the fax machine to get press releases and other printed info. Seems like a lifetime ago.
The 'net also can be an incredible timewaster, which is not necessarily a bad thing, depending on how much time you have on your hands.
Cyberspace is such a vast space that sometimes I wonder if there are sites waiting out there that I'll love, but I have no way of finding them. Searches are good, but what if there's fascinating stuff out there that I don't even realize I should be looking for?
Enter StumbleUpon. I haven't even surfed it thoroughly myself (not enough free time lately), but I gather it's links to sites recomended by other surfers.
Fabulous way to find interesting things!
As the 'net just grows and grows exponentially, the trick is going to be finding good portals for all the incredible amounts of info and user-recommended sites, as well as expert-recommended sites, are bound to be the way of the future.
Happy surfing,
Vanessa