Google Analytics is considerably better with a selection advanced segments, some basic segments have been added by the Google team already, while others are just a click away. The segment listed below is one of my favorite as it allows you to compare different traffic properties such as social networks Vs organic traffic Vs direct traffic in terms of conversion rates, bounce rates and much more.
It includes one filter to group all the different social networks websites to one new medium and a few advanced segments. Before you start, I strongly recommend to create a new profile for this segment as it includes a new filter (always apply new filters to a new profile and leave the master profile unchanged).
Stage 1 – create a new website profile and name it… Social Networks Traffic 
Stage 2 – group all the different social networks under one new medium by applying the following filter
Filter Name – social traffic
Filter Type – custom filter then advanced
Field A -> Extract A – under campaign source add your social networks (for example, I’ve used digg|aim|friendfeed|blinklist|fark|furl|misterwongs|wikipedia|stumbleupon|netvibes|bloglines|linkedin|facebook|del\.icio\.us|feedburner|twitter|technorati|blog|faves\.com|wordpress|newsgator|PRweb|msplinks|myspace)
Field B -> Extract B – none
Output To -> Constructor – campaign medium and name it social networks
Field A Required – yes
Field B Required – no
Override Output Field – yes
Case Sensitive – no
Now, under traffic sources > medium you’ll find a handy ’social networks’ traffic medium source which includes all the social websites
Stage 3 – click on advanced segments to create a new segment
Stage 4 – under dimensions open traffic sources and drag the ‘medium’ button to dimension or metric window
Stage 5 – under matches exactly option type social networks (the filter created before)
Stage 6 – repeat step 5 and type organic
Stage 7 – repeat step 6 and type referral
Stage 8 – result! just apply the new segments to the report and start optimising your content
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More great resources
Google Analytics official blog Advanced Segments & E-Commerce
Measuring Success blog Tracking social networks with Google Analytics using filters