skype uses encryption whereas google keeps your information logs... for voice and searches when searching for something illegal try to use Scroogle.com they keep your log searches for 48 hrs.
SIP over VPN. i use internetcalls.com or rynga.com
But i Mainly use for my call flooding service, as those SIP servers are configured in a way in which i can abuse them as long as i have a small 10 or 20usd account.