We all know about this very famous thing quora . it's a place where you can easily find out every answer of your questions .
So I consider this app as a very much helpful app.
If it's about any type of software , or if about personal relationship or anything whatever topics just ask your question and you will surely get a quick reply of your question.
When you download this app you will be asked about your topics you would like to explore , not only you can just ask question but you can also answer to some of the questions if you know the required answer , so I think everyone must have this app it's helpful a lot.
