Potential members are worried about two issues:
- Having their community recognized
- Not being overwhelmed with information
The method of differentiating the communities will be utilizing Tags. While tags are not defined, we might suggest an initial set of tags.
You can then watch the page, or follow an RSS feed for tags you are specifically interested in (someone want to get a couple reputation points adding a how to for this?)
Someone with a high reputation(300+) will need to initially create tags. But earning a reputation to be able to do such things is what make the community sustainable.