Most VCs delegate diligence to 22 year olds that don't really try the site or startup of the startup they invest in.
This should not be surprising.
VCs deliver risk-adjusted returns way below the S&P 500Most
http://www.avc.com/a_vc/2013/02/venture-capital-returns.html
http://www.kauffman.org/newsroom/institutional-limited-partn...
And VC's subtract value from the startups they invest in.