Yeah, irssi is running perfectly fine for last 20 years, icq, msn, Skype, discord, everything comes and goes, longins/password got forgotten and lost.

But there is always that irc channel easily to get into and will be there in 20 years.

I know that I can extend my irssi client with plugins needed to preserve history, flag stuff, save in database by triggers, then export that in whatever way I want and serve to the users.