There is a new service for finding out the company name, contact name and email address and other information of website visitors. It is an add-on to Google analytics offered by Fastbase.com. There is a free trial which lists leads to your site for the last 12 months. Here is the pricing page: https://analytics.fastbase.com/Pricing. The catch is that you have to login to your Google Analytics account and share your Analytics data with Fastbase. I do not know how they will monetize on having this data but it is valuable so I am sure they will do well!
I did a test for one of my clients and downloaded a list of 728 leads with a date range of 12 months. this is out of a total of 27,543 users to the site over the same date range. It remains to be tested to see if these leads are any good, but it could be a powerful tool for B2B websites. An extension on remarketing: rather than just showing ads to people who have been on your site you can actually contact them by email, phone or mail.
Out of the 728 leads, 623 had email addresses. I ran this list through zerobounce.com to get an idea of how many of the emails are valid (it is processing, I will include an update in comments.) It might be interesting to send out an email blast to this list to see what kind of interest you get.
Please leave comments if you have tried this service, have feedback or are interested in receiving these lead reports.