Even when openning anonymous tabs, cleaning cookies or using VPN you still share some important information that might open your identity. List of resources below shows how easily attacker may receive information that you think should be actually hidden.

Detect your internal network IP address

http://net.ipcalf.com/

Accurately get your location

https://browserleaks.com/geo, you may also check a lot of different data that your browser exposes at browserleaks.com.

E-tag

ETag - might be used to uniquely identify you.

Is your browser safe against tracking

https://panopticlick.eff.org check that here.

Information about your browser and computer

https://whoer.net a lot of data including IP, language, screen resolution etc might be found here.

DNS exposes you IP

https://www.dnsleaktest.com even if you are using VPN.

Check your location with MAC of your router

http://samy.pl/mapxss/ just enter MAC address of your router and see whether it has this vulnerability.

Take care!