There are two very different "startup scences" in the Netherlands. The social/cultural/financial startups seem to aggregate around Amsterdam. For the more interesting and high tech stuff you have to look at Delft, Twente, and in particular the Eindhoven areas. For food and agricultural stuff, the place to be is the Wageningen area. Often, from an international or Hollandish perspective, the Netherlands is equated to Amsterdam and vice versa, but that results in a very skewed image of the Netherlands and the startup scene in particular.
(For example, on the website you refer to, there seems to be only one Eindhoven area job and that's for front-end development to boot. Apparently, this website does not give a good representation of start-up jobs in the Netherlands, but focuses on Randstad webdevelopment jobs instead.)