Well, I knew this was going to happen eventually: Google now has global spam filtering for Google Voice. It works in a way very similar to how ISPs track the sending reputation of email senders based on feedback from their users (i.e. spam reports). Now, if you opt-in to Google Voice's new "Global Spam Filtering," calls and text messages from phone numbers determined to be "spammy" won't make your phone ring. They'll land in your Google Voice "spam" folder, out of sight and out of mind, until and unless you go specifically looking for them.
I think this a great idea -- collaborative reputation systems are cool. What do you think?