Yup, great community. Yup, building is better than talking.
Personally, I don't think marketing and communication is a waste of time, even for some one technical - especially when you are bootstrapping. For other folks, it's a login with OpenID, and a copy/paste of info they already have. It helps with page rank too.
HN is the community that you already want (need?).
If you've got an idea, just build it.
Stop wasting time wringing your hands and creating new groups.