Right on, and then I'd be able to assign tags to groups?
The ability to filter content to audiences based on my own
categorization would be the missing link. Right now I can partially
keep things separate by keeping work away from say youtube and digg,
but in reality my privacy/exposure in the end boils down to individual
items rather than streams. A slick way to set default tags per post,
per stream, that can then be customized per post to mix up your feeds
is really exciting. An even easier solution I suppose would be to just
add your groups to each item you're 'inta'. Then you would have a
default filter/exception.
Good luck anyways, it sounds like you know what I'm talking about.