http://42floors.com/blog/youre-not-anonymous-i-know-your-name-email-and-company/
Sumit Suman recently visited a site, did not sign up for anything, did not connect via social media, but got a personal email from the site the next day.
Here’s how they did it.
I’ve learned that there is a “website intelligence” network that tracks form submissions across their customer network. So, if a visitors fills out a form on Site A with their name and email, Site B knows their name and email too as soon as they land on the site.
For example, if [a visitor] went to XYZ.com and filled out a web form and then [the visitor] later visited 42floors.com, [42Floors] would be able to identify [the visitor] by name/email as well as company details even though [the visitor] never filled out a web form on [42Floors.com].
Remember, that thing that everyone always thought would never happen? There you go.
And no, this has nothing to do with cookies or IP tracking. This has to do with browser fingerprinting.