What do people refer to when they talk about browser fingerprinting?
What is the difference between browser fingerprinting and linkability?
Why is it important?
For what is it used?
Linkability tries to chain different information with the goal to deanonymize you or to find more information about you. Assume you use a browser where you sometimes use Tor and visit this site (Tor.SE). The site also loads contents from Google Analytics and Quantcast. If you're visiting any other site which also loads those components, regardless if you use Tor or not, Google Analytics as well as Quantcast might be able to link this information. This means they can say user X first visited Tor.SE and later went to site XYZ. In between those sessions he toggled Tor.
A browser fingerprint is a collection of info about a browser. When you visit a website, you send a variety of information, like screen size, installed fonts, and software versions; the site can also ask you for much more, as demonstrated by BrowserSpy. Like human fingerprints, browser fingerprints are usually unique. With your browser fingerprint governments and advertising companies can track you across the web, making a list of the things you've looked at, the places you've been, and what you've said and done.
Linkability is the ability to link two or more profiles, identities, or pieces of data. For example, imagine you have a Gmail account and a Facebook account; you have them registered under different names, and believe nobody can trace them back to you, or to each other. In reality, the advertisers and government agencies have linked you to both of them by using your browser fingerprint to follow you across the web.
Device Fingerprinting (Under the JS Display menu, cursor position is among the reported data.)