What tools, platform would you recommend if someone were to build a portal ground up with the following features:<p>a) Ability for users to upload (or share, link) user generated content (say, audio, video, images etc)<p>b) Ability for users to comment, rate and provide feedback on user generated content<p>c) Ability for portal owner/ admin to do analytics (page views, visitors from different countries, downloads etc)<p>I don't want to write everything from the scratch but instead want to leverage existing tools/platforms as much as possible.<p>Thanks!