I'm writing this topic because these days I've read that a chat that I used regularly until a few years ago will close down definitely in the early days of 2024.
The name of this chat is sMeet, it's a browser-playable 2D chat based on flash player. It was very popular around early 2010 as it was included in the collection of flash games featured on Netlog (another historic social network). It quickly managed to gain popularity and an increasing number of users, until it began its slow but inexorable decline when major browsers dropped support for flash player.

In early 2011, many users of the Italian sMeet community (including me) began to massively migrate to IMVU and for a few years there was a strong link between the two social networks, connected by many members of the community.

Obviously sMeet isn't the only social networking reality that's being shut down permanently. Netlog itself, as many others such as MySpace and MSN, suffered the same fate. Let me also mention Google Plus, although it lasted too short for anyone to remember it

So many others are social networks that were in the spotlight until a decade ago and now have literally fallen into oblivion, leaving the stage to more modern platforms. There are so many and them makes me remember that the years have passed for me as well.

I mention the most well-known ones, there's still nowadays someone who actively uses ICQ, XMPP or IRC (by actively using I mean using software that directly accesses these protocols)? Two of these (XMPP and IRC) are open source protocols still used today mainly by insiders or nostalgic but they have unfortunately lost that large segment of users who, perhaps unknowingly, used them daily through a variety of instant messaging application (Google Talk for example, also defunct, used XMPP as a protocol).

Very few stand the passage of time, including IMVU, which nonetheless (credit where it's due) tries to stay abreast of changes.

https://youtu.be/oMMloO4Yd00?si=oQSmy_V42t-PIN8Y

Ryze and Orkut were probably my first. Felt very weird and publicly “exposed” putting anything there. I couldn't see why I'd want to “announce” anything to a group, rather than tell the one specific person it was meant for. Didn't seem much more than bulletin boards that had gone digital. And I never had anything, I'd have wanted to pin on a bulletin board - even one in a private club.
Facebook gave me my first motivation to really get more active - because I could find friends, classmates and relatives, I'd lost touch with. And they had some really addictive games. This is all that was till 2009 - the early days.