And all the obvious problems with a public serchable IRC channel that logs all history.
Twitter "ruined journalism" by giving lazy media companies a way to "track big stories" (i.e. a few thousand people comment about N and that's News, apparently.)
Facebook "ruined journalism" by virtue of users not bothering to read the news at all.
Both are horrible.
But, facts, "Journalism" was ruined by corporate interests decades ago.
And drug lords have built soccer fields for the poor and dictators made freeways and cheap cars and rockets
I'd say FBs semi open source (not fully unrestricted iirc) was less unique or inevitable that the good actions of other notable evil organizations
My main problem with it is that it doesn't obey its own filters very well. If I search for "Buick" and set a radius of 40 miles from my location, it might give me a few within that radius but then start giving me a bunch from hundreds of miles away. And it doesn't seem to work outward, but might give me some 500 miles away and then one 50 miles lower down. That makes it less useful than it could be.