> Together’s $20M seed funding to build open-source

This is a huge contrast. Stability AI’s bread and butter is proprietary, not open source. Together seem to have a track record of open sourcing both code and models.

To be fair, Stability AI have open sourced StableLM, which is welcome. But overall Stability exaggerate and lie about their openness.

It doesn't sound like it's trying to build a single model, it wants to build a network/community of them. One of which is their own. Probably sharing/coordinating training resources and other support systems? The things that are usually out of financial/technical scope for most smaller OSS AI projects. I could see smaller companies with open models spending to be a part of that or other financially backed OSS projects.

Maybe it's more hands-on than just a hosted service like huggingface? I don't really know the market, so just speculating.

Stability AI is also no longer open. They seem to be commercializing SDXL and it's not open - "yet".

Different investors.