Pretty much a marketing term. It's basically processing of data of an undetermined size, deemed to be "big". You might consider Google or Facebook as companies

Pretty much a marketing term. It's basically processing of data of an undetermined size, deemed to be "big". You might consider Google or Facebook as companies that process lots of data, so you might consider their operations as some on "big data". It is pretty much just a marketing term now though - "big" is insanely relative.