Google's Gmail Labshas just rolled out a useful, but mildly creepy feature that gives you suggestions on who you should e-mail
based on previous conversations. So, if you've had threads going with a
group of people, it will recommend some of those folks once you've
added at least two addresses in the recipients field. Best part is,
they don't even have to be in a group of contacts you've created in
Gmail's contacts manager.
I got this to work to an almost uncanny level. It handles things
like family members without a hitch, but where it gets useful is in
pulling up people you've recently been corresponding with and giving
you a one-click link that adds them to the message. Short of organizing
these people to a group (in which you may need to add or delete someone
on a per-message basis), or doing a reply-all on an old message, this
is a really fast way to get another thread started with the same group.
Now all Gmail needs is a quick way to take these contacts and add
them to a sending group without leaving the message, something that can
only be done in Gmail's contact manager.
can now figure out if you're trying to start up another conversation
thread with people you've recently been talking to, saving you some
time on starting a new message thread, or simply using a reply all on
an old one.