Leadfeeder - Leadfeeder converts your website visitors into sales. Connect your website's Google Analytics to Leadfeeder and unlock the power of seeing who`s visiting your site!
fruux - Free service that takes care of your contacts, calendars and more so you don't have to.
Visitor Queue - Better identify the companies that visited your website!
FullContact - Put the power of full contact information into your web or mobile apps.
Elucify - A completely free software tool that uses crowdsourced data to find business email addresses
Google Contacts - Google Contacts is Google's contact management tool that is available in its free email service Gmail, as a standalone service, and as a part of Google's business-oriented suite of web apps Google Apps.