I used to use TES under a different but related username. Workplace Dilemmas was so helpful; I can't remember the name of the lovely lady who retrained as a lawyer and gave such amazing advice, then was diagnosed with something like leukaemia. I do remember Lilyofthefields too.
The subject forum was really helpful. As a music teacher, in a 1.5 person department, you could ask for suggestions there. A couple of posters were bloody irritating but one, Florian Gasman was extremely knowledgeable, especially on niche A level topics, UCAS or conservatoire applications. My HoD and I used to wonder where this particular poster came from or worked.
Now, I use the Facebook forums. The Music ones are pretty helpful, especially the exam board ones for KS4 and KS5 as the subject officer is a regular contributor. At all key stages, posters willingly share resources or signpost things they have found, which during lockdown, saved hours of work. A couple of my old uni friends are on there too, some 30+ years after graduating.
I don't post much here but I do read. Unlike some parts of MN, I have found the staffroom to be friendly and supportive. So on that note, I hope you all have a safe end to the year and wish everyone the very best for 2021!