I need to create a website utilizing open source software to save on development costs. The main function of the site is a directory that will allow user reviews. In addition to the directory/reviews I want a user profile/social networking component to the site. I also want the ability to scale the site in the future by adding a forum, articles, blog, media content, etc.

I have found directory services such as PHP My Directory, JReviews for Joomla and various review scripts. I have also discovered a variety of Social Networking apps such as Ning.com, but I haven’t found one solution that satisfies all of my needs.

What is the best way to create a site that is 1 part social network, 1 part directory and 1 part reviews? If I use multiple scripts I’ll need them to tie in together so that the users have only one log-in to access their profile, reviews, forum, etc. This site is essentially going to mirror yelp.com in functionality. If you have any suggestions I would greatly appreciate it. Thanks!