There are many commonly performed operations that can take a long time to execute. For example:
Web service invocations
File downloads and uploads (including for peer-to-peer applications)
Complex local computations
Local disk access, given its slow speed relative to memory access
On MSDN http://msdn2.microsoft.com/en-us/library/8xs8549b.aspx
The opinions expressed herein are my own personal opinions and do not represent
my employer's view in any way.