Mh.. there are some open source applications that one could use to build a social network Elgg Dolphin JCow Oxwall Beatz Budypress I haven't used any of them, so you have to search a bit and decide which one to use
There are only just a few good social networking scripts around. Actually 3 well known and solid, they exist for many years already and have good support too and private forums. phpFox - http://www.phpfox.com (the best of the 3) Social Engine - http://www.socialengine.net Jomsocial - http://www.jomsocial.com (this is a Joomla component, Joomla itself is free)
No sweat. If you don't have the wind to knock it up with Elgg... phpfox is the answer really. Dolphin sucks and while anything baked into wordpress is tits, buddy press is not the answer either. N.
I would recommend this one http://chameleon.startsocialnetwork.com/ and change it to your liking here http://www.abk-experts.com
It would be the best option to have one developed for your immediate requirements an then expand it as you grow.
I I don't agree with you guys mentioning that Drupal is good for social networking at all!... You have no friend list, you cannot sent private messages, it is not possible to have your profile page, your gallery with pictures... Many of these things can be possible, but the integration between them is not good... Drupal for social networking requires lots of customization...