Was feeling a little nostalgic for Google Wave. Turns out that came and went between 2009 and 2010. Apparently Apache messed with it for a while, and only officially stopped development in 2018 (https://en.wikipedia.org/wiki/Google_Wave).
Then I remembered Google+. I had some hopes already back in the early 2010s that at least Google+ could give FB and Twitter some competition. On paper it existed 2011-2019 (https://en.wikipedia.org/wiki/Google%2B), but really it was officially killed on October 8, 2018.
While I was looking up Google+, that wikipedia page reminded me about Orkut. Remember Orkut!?! (https://en.wikipedia.org/wiki/Orkut) Turns out that as of April of this year, the website is back up: http://www.orkut.com/index.html
See you there?