Even without [[Third Party Cookies]] tracking can be done by identifying browser characteristics.
Using OS, CPU details, clock skew, time zones, display settings, installed front and plugins to build a fingerprint for a device.
Using graphics (html5 canvas) rendering differences to identify users by GPU.
Fingerprinting with IP address, OS, user agent, language, accept headers, etc.
- Cover Your Tracks (eff.org) includes a browser fingerprinting check.
- Am I Unique ?