"General industry estimates on the use of open source software
in some fashion or another ranges from about half to even 90
percent of companies with significant programming staffs. But how
often the boss knows about it, or perhaps more importantly: How
often open source gets the proper review is a far lower figure.
"Forrester Research's Ted Schadler said his firm does not have
figures on the number of companies or agencies using open source
without the higher-ups knowing about it. [The author has heard a
lot of 'You're asking people how much they don't know' in
researching this story.] However, Schadler--who agreed it was an
interesting query--did study the open source adoption 'funnel'
earlier this year..."