Oops, missed this:
> The ability to email groups rather than log in to post would also be a big advantage (although not as important as the notifications).
This appears to be impossible – we couldn’t find a single piece of software that allows it, as this was the team’s first thought for moving on from LISTSERV email distribution lists such as PTNC. There is a fundamental incompatibility between “send one message to many people” and how social networking sites operate. I find that intriguing, given that people can email to blogs, but there we have it.
Maybe you could let us know if you find an equivalent site / software / etc. which provides this? Maybe something will develop? Jon