Usurv asks 100’s of people to answer questions. This contrasts with services like Yahoo Answers where often only one or two people may give an answer to a specific question.
The type of questions that can be asked are also different. Usurv's questions are structured where a list of answer options are presented to potential participants (e.g. Which of these contestants do you think will win the X Factor? / Would you recommend your mobile phone to friends / family).
Using a service like Yahoo Answers, the questions are not structured (e.g. Why is the sky blue?) and there is no pre-defined list of answers.