Think about the first instant messaging service that you used. Chances are it has been discontinued many years ago and got replaced by today’s giants such as Skype or Discord. Except that there is a chance someone revived it!
Introducing the Escargot MSN Server. Since 2017, you can use your favourite (supported) version of MSN Messenger once again whether if it’s for nostalgic reasons or just for fun. Follow the instructions, insist your friends to use Escargot and voilà! You’re back in 2005.
Some versions has more bugs than others, and not every function is supported yet but regular instant messaging is in working order.
If you want to find out more, you can visit their website: https://escargot.chat/
Edit 1 May 2021: Escargot link updated (from the old https://escargot.log1p.xyz/)