I might end up starting another Social Extensions debate here but i havent come across a blog or article that addresses a large cross section of them. I wish this turns out to be more of a bloggy discussion than just a blog ..
With the web landscape littered with a lot of software to create your Social network both in & outside the Joomla Community, it becomes increasingly difficult to find which is better.. Within Joomla there is CB, JomSocial, People touch to name a few.. I have heard of at least a couple more of these which are in their last stage of Beta & would be released soon.
Wordpress press has Buddypress while Drupal has quite an array that can be put together to pull together a decent community. On the SAAS front you have NING which has been very successful in letting people create feature rich community sites. Joomla is well represented on Ning with www.alltogetherasawhole.org .
Social Engine has also managed to carve itself a large slice of the Social Engine Market.So here is a small poll that we'd love if you answer telling us your preference in developing Social network sites. Since Joomla Polls does not support multiple choices i have set the lag to just 10 seconds so that you can vote multiple times if you use various systems.
Please comment comment comment & add your inputs. I know this is a pretty small list we have here just thought of on the spur of the moment.. so I'd like you to add as much as you can !

