Many a time developers need random user data to quickly churn out a proof of concept. The following are great services which provide random user data:

Fill Text: Personally this is my favorite for the fact that it has an awesome and extensive RESTful api that pretty much caters to most of your needs.

RandomUser: It is a A free API for generating random user data. Like Lorem Ipsum, but for people. A great feature of this service is it also provides you with links to user images.

GenerateData: This is a great resource to generate user data in a variety of formats. However it does not provide a RESTful api.

JsonGenerator: As the name implies it generates json user data. It is little cryptic, but pretty effective nonetheless, it does not provide a RESTful api.

Links:
Fill Text
RandomUser
GenerateData
JsonGenerator