Google Voice has been a boon for those of us who are uber-discerning when it comes to answering the phone. It's sometimes too vague to simply screen all of the calls and forward everybody to the same bland voicemail message. However, the ability to group your contact list into groups and then assign a different voicemail message to each of those groups has, thus far, been limited to only contacts that you have stored in your address book. And if you're like me, you probably hesitate to answer any unfamiliar numbers that aren't already stored in your phone. More, if that number shows up as blocked, you probably never answer it.
Hopefully, today's update from Google Voice will help you better screen those calls from unknown and blocked numbers. In the announcement, Google Voice announced that users will now be able to create a unique voicemail greeting for numbers already saved in the address book but also maintain a second voicemail greeting exclusively for people who haven't had the good grace to be saved into your phone. I imagine this might be helpful if you worry you feel a little wooden over the phone to your friends and family but don't want to sound too casual if you regularly receive professional calls from unfamiliar numbers. Think of this new ability to have difference voice messages for your Knowns and Unknowns as the mullet of wireless communication: party in the back for all your familiars, business in front for all the callers you aren't so well acquainted with.
Or, if you just don't like getting calls from unfamiliar numbers and would rather screen those presumptive telemarketers into the bugger off bin, you could utilize the Anonymous Callers group in like fashion.
You'll find the option for these two groups in the drop-down gear menu on the right under Settings. Once you're in Settings, click on Groups & Circles and the new group options will be at the top: