As for Twitter? Well that'd be a bit more of an issue, though I'd probably move to a competing service like Mastodon/GNU Social or Gab.
Still, I'm not exactly a social media addict, so I guess it'd be more interesting to hear what'd change for those.
Never used Twitter or wanted to.
ps Why would the world fall apart if Google disappeared? It's not obvious to me.
I'm sure many industries are supported with the likes of "Just Google it"
Malaysia in particular is vulnerable to propaganda, because political parties own all the major free channels and newspapers. Social media has helped balance it. While the government has blocked Medium, places like Facebook and Twitter bring world news to the masses, including any stories like local corruption that a news site like WSJ would investigate but none of the local ones could.
Also about 80% of my jobs come from Facebook connections, so it is very valuable to me.
If both of those went down, we'd probably move to Reddit, Instagram, LinkedIn, Pinterest. I think those sites are even worse for society.
Twitter: no effect whatsoever.
Twitter: I think I'd lose access to a lot of real-name graphics/game programmers who I like casually interacting and sharing with. On the other hand, I'd be spared their frequent overbearing political opinions.
I don't get my news or amateur opinions from social networks so it doesn't affect me there.
I do use Netflix though - ad-free entertainment for less than £8 a month - bargain!