Quora is a free app connected to the ask-and-answer website of the same name. On Quora, people ask questions about a huge variety of subjects, and other users (who are generally enthusiasts or knowledgeable about the subject) provide various answers. Answers are then rated, a credit of sorts is earned by the one answering, and all involved move on to more questions and answers. It's a great app to use for something specific or simply to browse.
Ask a question, and wait patiently for the answer
The Quora app itself is easy to use and fast. It works as well or better than viewing the website on a browser. Notably, one account lets you both ask and answer questions. The only problem is that it can take a while for other users to respond, though not always.
A potential source for all life's questions
The Internet, as a whole, hasn't gotten to a point where the answer to every single question is recorded somewhere. But Quora provides a way to ask questions that the Internet can't yet answer through a simple Google search, or what have you. In this, it serves a fantastic purpose. And it's also worth downloading just to browse and learn... or to answer questions yourself.