Bulk Email Verifier - Clean up your large mailing lists before you use them. Clean list increases your reputation in MailChimp, AWeber, or Campayn.
RingLead - RingLead offers a complete end-to-end suite of products to clean, protect, and enhance company and contact information.
Email Verifier - Email verifier app lets you verify email.
BizProspex - BizProspex offers CRM data cleaning solutions.
Email List Verify - The Fastest Way to Improve Email List Deliverability and ROI
TowerData - demographic data on email addresses