This informative article from Internet Storm Center shares browser tracking techniques

There are a number of different use cases to track users as they use a particular web site. Some of them are more “sinister” then others. For most web applications, some form of session tracking is required to maintain the user’s state. This is typically easily done using well configured cookies (and not the scope of this article). Session are meant to be ephemeral and will not persist for long.  Over the years, browsers and plugins have provided a number of ways to restrict this tracking. Here are some of the more common techniques how tracking is done and how the user can prevent (some of) it:

1 – Cookies
2 – Flash Cookies (Local Shared Objects)
3 – IP Address
4 – User Agent
5 – Browser Fingerprinting
6 – Local Storage
7 – Cached Content
8 – Canvas Fingerprinting
9 – Carrier Injected Headers
10 – Redirects
11 – Cookie Respawning / Syncing