<p>I'm planning on creating a social networking + MP3 lecture downloading / browsing / commenting / discovery website using Ruby on Rails. Partially for fun and also as a means to learn some Ruby on Rails. I'm looking for a social networking framework that I can use as a basis for my site. I don't want to re-invent the wheel. </p>

<p>Searching the web I found three such frameworks. Which of these three would you recommend using and why?</p>

<p><a href="http://portal.insoshi.com/" rel="nofollow noreferrer">http://portal.insoshi.com/</a></p>

<p><a href="http://www.communityengine.org/" rel="nofollow noreferrer">http://www.communityengine.org/</a></p>

<p><a href="http://lovdbyless.com/" rel="nofollow noreferrer">http://lovdbyless.com/</a></p>

I've not worked with these but am aware of this comparison:
"Unlike Insoshi and Lovd By Less, which
  are full social networking Rails
  applications, Community Engine is a
  plugin that can add social networking
  features to existing Rails
  applications"
from
http://www.rubyinside.com/community-engine-rails-plugin-that-adds-social-networking-to-your-app-901.html