Actually, while there is pinboard.com, which, as the author points out, is not free (which brings to mind: how, really, do you want to pay for your free lunch?), there is a free - and open source - platform [1] that, in my opinion, is far more powerful than was Delicious (I was an early Delicious user).
I'll offer a side observation: when people don't pay for sites like Delicious (and Facebook and ...) the Signal to Noise Ratio falls off dramatically. What, contrary to the author's claim, you might need is not so much a wider audience for "more stuff", but, instead, an audience which has a stake in the value of that "stuff".
[1] https://web.hypothes.is/
I'll offer a side observation: when people don't pay for sites like Delicious (and Facebook and ...) the Signal to Noise Ratio falls off dramatically. What, contrary to the author's claim, you might need is not so much a wider audience for "more stuff", but, instead, an audience which has a stake in the value of that "stuff".