Sometimes a story or idea goes viral because it's too big to be ignored. But more often it's because a single human being passes it along to an audience that's either massive, highly influential, or both. There aren't too many people who can do that.
StumbleUpon is great for finding interesting stuff that is off the beaten path. A post here, a URL there and suddenly you find yourself reading some incredible content. The iPad is perfect for this type of browsing, but StumbleUpon's tablet app was woefully inadequate until now.
StumbleUpon, an excellent service for finding cool websites, just launched App Discovery for Android, aiming to help users find something even more elusive than cool websites: cool apps! It'll look at the apps you already have and suggest similar ones.