The article covers some basic things - as for VPN provider some store a lot of logs about user activity (avoid such services), some have 100% zero logs policy,

The article covers some basic things - as for VPN provider some store a lot of logs about user activity (avoid such services), some have 100% zero logs policy, and are based in countries that don't stick their noses to internet traffic. About TOR's exit node - article mention at the beginning about how packets travel, so it's obvious that potential spy doesn't know who you are....until you do something stupid like logging to your gmail, or facebook. So unencrypted traffic at exit node can be used to track you down.