4. Google Voice
If you have a gmail account, you can use it to make phone calls to those on your chat list, as well as receive them. The new product from Google is catching on fast and allows users to block calls by enabling a feature to block unwanted calls, abuse, and spam.
To enable this feature on Google Voice simply:
1. Click the wrench icon and select Settings.
2. Click the Calls tab.
3. Check the box next to Global Spam Filtering.
