How do you find a coins network hashrate?
I see pools will post that statistic or occasionally people post outputs like this;
Network HashRate (16 block estimate)
448.89 GH/s
Network Hash Rate Needed to find block on time (10 minute interval)
142.91 GH/s
Current Block Information
Block Number: 23260
Time: 2013-04-20 01:12:23
Difficulty: 19964.21586947
Where is that information being queried from?