V12 Data - V12 Data offers rich data sets with verified addresses and emails for personalized marketing campaigns.
Survey Monkey - Create and publish online surveys in minutes, and view results graphically and in real time. SurveyMonkey provides free online questionnaire and survey software.
Adobe Audience Manager - Adobe Audience Manager is a data management platform that integrates online and offline data to deliver a unified view of all your audiences
Qualtrics - Qualtrics is the most trusted research platform, helping brands make crucial business decisions. From surveys to insights to action.
Clearbit - Clearbit provides Business Intelligence APIs
Google Audience Center - 3 votes and 6 comments so far on Reddit