they company behind also runs videoblocks and audioblocks. and they buy most of the content (resell license).

here is a short report:

Today Holland�s company, Video Blocks, is a leading online stock footage vendor with projected 2013 revenues between $12 million and $15 million, double last year�s total. Based in Reston, Virginia, Video Blocks hires freelance videographers to shoot original clips that the company owns. The company also buys nonexclusive rights to existing video content, and operates a studio where it shoots original material.

"Everybody else is trying to sell by the drink," says Carter Griffin of Updata Partners, a Washington, D.C.-based venture capital firm that invested $10 million in Video Blocks at the end of 2011. "Joel has a different and better business model."

So they have a lot of money to buy resell rights and to produce new stuff.