I like this explanation http://www.ericsink.com/item_10174.html http://www.ericsink.com/item_10174.html from 2004 from Eric Sink, and this recent application

I like this explanation http://www.ericsink.com/item_10174.html http://www.ericsink.com/item_10174.html from 2004 from Eric Sink, and this recent application of his own advice http://www.ericsink.com/entries/mobile_database_sync.html http://www.ericsink.com/entries/mobile_database_sync.html