dug 
Just noticed the flashing red more Labs! new new new! link at the top of Gmail. I’ve sorta stopped checking recently, bit of innovation overload… but this sucker is fantastic.
Now, I’ve designed a number of messaging systems over the years, including two very large and complex (and supposedly integrated) ones for mobile operators. In all cases, the following user need rated highly in the business requirements/user needs matrix:
I need to feel confident my message will go to the right person
Doesn’t seem like too much to ask, does it? Even so, once you start thinking about it, the number of really embarrassing usecases where your message is not routed as you expected are really quite staggering.
In any case, Gmail has just launched an addressee disambiguation system which doubles as a system to identify and recommend potential groups.
(From the Google site:)
Whats new in Labs: "Got the wrong Bob?" and "Don't forget Bob"
Ever included Bob (your boss) instead of Bob (your friend) on an email by accident? Oops! Turn on “Got the wrong Bob?” and Gmail will check if you meant to include Bob Smith rather than Bob Jones based on the groups of people you email most often.
With “Don’t forget Bob,” you can start composing an email to a group of people, and Gmail will suggest other contacts you might want to include. Check out these experimental features and more on the Labs tab under Settings.
Awesome, thanks Lab guys :-)