Play Framework, Django or Rails? Which one do you recommend for Social Networking Web applications.
Both Rails and Django have been used for a large number of high profile social networking web applications. Off the top of my head, Django is used by Instagram and Pinterest, Rails is used by Posterous and Ravelry. I don’t know what the largest sites built using Play are at the moment.
The hard problems involved in building a social network are essentially framework-agnostic: things like scaling an activity feed and running queries against large social graphs are solved by smart application architecture, not built-in framework functionality. Whether you use Rails, Django or Play will have almost no effect on how you solve those larger architectural challenges.
Pick the one you are most comfortable working with and start worrying about your site’s functionality rather than its application framework.