I doubt StumbleUpon would be able to take off in the same form today - it installed a browser toolbar, collected a profile of your interests, and collected your up/downvotes to fed them all to an opaque algorithm that took you to the next random page. Who knows where that data went.
Could we come up with a privacy-preserving equivalent to stumbleupon today?
Firefox’s Pocket recommendations took a good approach. The browser downloads a big daily file with “potential recommendations”, then filters it at the client side.
The big downside was that, because it was turned on by default, a whole bunch of people who didn’t actually want it had it foisted upon them, so it got a very bad reputation right out the gate. Right algorithm, bad execution.
I actually really like Pocket's recommendations, but yeah, the way it's all forced on you it's basically an ad. That's pretty much why I feel like I have to boycott it despite liking the product. It's such a Mozilla move to take something nice and turn it bad for no good reason.
At inception it was just a website that redirected you. There are variations of this created all the time but centered around essays and journalism. It would be trivial to create what is basically a glorified copy of SU, but no one cares enough to do it. Or more accurately, they already exist and we collectively don't care enough to notice.
Could we come up with a privacy-preserving equivalent to stumbleupon today?