Not everyone like to use Twitter or Facebook.
I have not used Twitter in years, and the only reason I have a Facebook account is for connecting with family and friends worldwide [that share photos and such on Facebook].
Most communications, that are not face-to-face or over the phone, are done via email. I prefer this.
"tools of the 90ies"? Well so are desktops, laptops, web servers, and other tech that is the foundation of what we use today.
As for "Twitter", well the national news has stated that Twitter, and some other social media outlets, are downsizing due to the lack of use.
Also, a case for email lists, it is hard to keep out the "trolls" on social media than it is on an email list. There has been many cases of misinformation placed on social media just to cause trouble for individual, organizations, and businesses. I really do not want to see something like that for our "help services".
I may be wrong, by the opinions of others, but I trust managed/monitored email help lists over "social media" sites for helping me with any problems I may have with LibreOffice.