Thanks Nathan.
Both those communities are excellent, but they have different flavours so they may suit different people.
OpenPnP is an active community that is very focused on the OpenPnP software itself, and machines to run it which can be either DIY or conversions of commercial machines. It's not a place for general discussion of broader issues. But if you have a DIY machine, or you want to retrofit an Open Source control system to a commercial machine, it is THE community to join.
The best way to interact with the OpenPnP community is via Google Groups:
Opulo is focused on their own commercial desktop PnP product (LumenPnP) which is Open Source to the core, and they have an extremely active Discord that is far broader than just their machine. There are busy sub-groups that discuss solder stencil printing, parts sourcing, reflow issues, tariffs and HS codes for parts ordering, designing your own feeders, and many other things. Opulo uses OpenPnP on their own product so there's also a little bit of discussion of OpenPnP, but nowhere near the depth or focus of the OpenPnP group itself.
The way to interact with the Opulo community is via Discord. There's an invitation link on this page:
If you're interested in PnP, both groups are great.
Jonathan Oxer