My current Tcl/Tk project is a usenet/web gateway. This involves a backend Tcl process (no Tk) which uses https://core.tcl-lang.org/tcllib/doc/trunk/embedded/md/tclli... to read articles from an NNTP server, and https://code.ptrcrt.ch/retcl/doc/tip/docs/index.html to cache these in Redis. Then each user gets a front-end Tcl/Tk process on the same server which reads articles etc. from the shared Redis cache and presents them in a fairly simple GUI. I use https://tktreectrl.sourceforge.net/treectrl.html to show newsgroups and article threads in tree structures. The GUI can then be used remotely in a web browser via https://wiki.tcl-lang.org/page/CloudTk (which is built on top of http://standard.prd.co.uk/man/tclhttpd.man).