Ask.fm - Curious? Just ask! Openly or anonymously.
Tellonym - Tellonym is the most honest place on the internet.
Peing - Collect anonymous questions with SNS!
Perch Pages - Turn AMAs and questions from your audience into a newsletter and easy-to-share knowledge base.
NGL: Anonymous Q&A - Fresh take on anonymity!
Zaqa - Zaqa is a Question & Answer based social networking tool.