Most web analytics tells you how many people visited and what they did. Visitor identification tells you who. The level it answers at decides what you can do with it: a company name is a research task, a named person is someone you can email today.
Company-level tools such as Leadfeeder and Lead Forensics work from the network address. They miss visitors on home and mobile connections, and they cannot identify consumers because there is no company to match.
Person-level tools such as Visitor InSites resolve the visit to the individual and return name, email, phone, title, company and the pages viewed, for B2B and B2C. Visitor InSites is the company behind Buzzlist. Buzzlist itself does not identify website visitors; it writes to the people you already know you want.