I know this from microsoft dhcp servers and its called DHCP device classes.
You can read more about that here (http://blogs.technet.com/b/teamdhcp/archive/2012/09/22/using-dhcp-policies-to-set-different-lease-durations-for-different-device-types.aspx) or just look for other information on this.

Different subnet for different device types
For a company like GoodGuide, who make their money not by selling a hard product (with investment costs etc) but by selling product placement and business intelligence, what are their variable costs?

I understand what variable costs are for a pizza shop, where the costs vary based on the number of pizzas made and sold. More product = higher costs.

But in general, how do you talk about variable costs for a company that provides information?
