and in the couple of cases I have seen it, it's mostly for hardware/ infrastructure related stuff? why is that?
-- Blekko: http://www.techcrunch.com/2008/05/14/stealth-search-engine-blekko-gets-money-from-marc-andreessen-softtech/
-- Facebook: http://www.businessweek.com/technology/content/may2008/tc2008059_855064.htm