I can fondly remember a time back when nostalgia did not get such a bad rap ;-)
The alluring thing about the past we remember is not whether it was better or perfect, but that there is no uncertainty about it. Whether it's true or accurate matter not, but we have a perhaps sugar coated, but largely fixed, reliable perception of it. Compare that to peering into murky unknowns, the possible dangers ahead, it's no surprise the road we traveled looks good.
I'm not looking for any platform or tools or glued together (;-) tools to find that way forward. The answer is definitely between keyboard and chair. All of us.
No matter where I come across you- your blog, in your photos, your tweets, an email, when we are together, there is a "Darcy-ness" that comes across all the channels. Sure it's constructed over time, shared experiences, and is only my collage of you. But as it evolved, I can know it where-ever we interact. I've seen your son grow up, I have eaten on your house (and left hair in your shower). But the thing I can know for sure, and it's not just looking back, is that I can count on you if I needed to ask for something, and not just technical.
That's not nostalgia, that's more.
We seek these strong connections, but now we want to shortcut the process with "tools" and algorithms, and one click friendships. It's an illusion.
And I had no idea our connection through blogging was superficial! Short of my immediate family, my one close friend from high school, the most important people in my life are friendships forged through many different channels, over time. Time. And effort. And giving to others, and getting from others.
I agree it's not an answer to go "quiiter" (though I urge everyone to quit Facebook, that's just my hangup;-) nor just a "go back to blogging", but just do what you phrase as How to questions:
1) be meaningfully connected to people we care about, in various ways as appropriate
2) publish relevant bits of our own digital lives in a way that we maintain control and autonomy
We need not look for a "how to" but just a "do"-- in whatever platform, tool that works.
Seems pretty simple to me.