OnMSFT.com started out (known then as WinBeta.org) as an ICQ channel back in 1998, and since then the site has run on a variety of platforms and technologies. Here's what we're currently using as of our latest update in March 2021.
OnMSFT runs Ubuntu 20.04 and Nginx on a single Azure VM with 4 cores and 32GB memory, with a 128GB Premium SSD for storage. We run a dedicated VM instead of an Azure web app to be able to host a MySQL server, as it's actually a bit cheaper and allows for full control of the VM. In our latest update, we moved to a new VM, updated to the latest versions of Ubuntu, MySQL, PHP, and Nginx.
When we switched from WinBeta.org to OnMSFT.com, we also moved from Drupal to WordPress.org. Our latest theme update, as of March 2021, is based on GeneratePress, and was developed by Ravenous Raven Design.
We use Disqus for our commenting system, and host all of our comments on Disqus.